db: business-layer schema — ledger/device event split, tariffs, permits, sessions

Implements the wiki design in packages/db + packages/shared.

Event split: rename events -> ledger_events (signed business ledger) and add
device_events (unsigned telemetry). ledger_events gains a signed JSON payload
(amount/tariffVersionId/sessionRef/tender…) + keyId; canonicalize() includes
the payload via sorted-key serialization so business data is tamper-evident.
Raw Dingtian input now writes device_events, not a signed input_received.

New tables: tariffs + immutable tariff_versions (composable/versioned, currency
+ FX-ready), permits (+ permit_credentials, permit_plates; maxConcurrent default
1), blocklist, sessions (rebuildable projection cache — not a source of truth).

shared: split ParkingEvent/Type into LedgerEvent/LedgerEventType + DeviceEventKind;
add LedgerPayload, Tender, TariffStructure/TariffBlock.

Regenerated a single baseline migration (no production chain data existed).
Verified: chain appends + verifyChain ok; tampering a payment payload breaks
the signature. Full repo builds (5/5).

apps/server/src/event-log.ts

@@ -1,6 +1,6 @@
 import { createHash, randomUUID } from "node:crypto";
-import { desc, events, type Db, type EventRow } from "@parking/db";
+import { desc, ledgerEvents, type Db, type LedgerEventRow } from "@parking/db";
-import type { Direction, IdentitySource, ParkingEventType, Signer } from "@parking/shared";
+import type { Direction, IdentitySource, LedgerEventType, LedgerPayload, Signer } from "@parking/shared";
 
 // The append-only, hash-chained, signed event log — the system's core anti-fraud
 // primitive (see wiki/concepts/append-only-event-chain.md). Entry/exit and device
@@ -16,11 +16,13 @@ import type { Direction, IdentitySource, ParkingEventType, Signer } from "@parki
 //    so we guard it with an in-process async lock as well.
 
 export interface AppendInput {
-  readonly type: ParkingEventType;
+  readonly type: LedgerEventType;
   readonly lane: number;
   readonly direction?: Direction | null;
   readonly source?: IdentitySource | null;
   readonly identity?: string | null;
+  /** Type-specific business data (amount, tariffVersionId, sessionRef…). Signed. */
+  readonly payload?: LedgerPayload | null;
   /** Event time (ISO-8601). Defaults to now. */
   readonly occurredAt?: string;
 }
@@ -39,6 +41,7 @@ export function canonicalize(e: {
   lane: number;
   source: string | null;
   identity: string | null;
+  payload: Record<string, unknown> | null;
   occurredAt: string;
   prevHash: string | null;
 }): string {
@@ -49,11 +52,33 @@ export function canonicalize(e: {
     e.lane,
     e.source ?? null,
     e.identity ?? null,
+    // Payload is part of the signed form so business data is tamper-evident.
+    // Serialize with sorted keys for byte-stability (object key order must not
+    // change a signature). null when the event type carries no payload.
+    canonicalPayload(e.payload),
     e.occurredAt,
     e.prevHash ?? null,
   ]);
 }
 
+/** Deterministic (key-sorted, recursive) JSON for the payload slot. */
+function canonicalPayload(p: Record<string, unknown> | null | undefined): unknown {
+  if (p == null) return null;
+  const sort = (v: unknown): unknown => {
+    if (Array.isArray(v)) return v.map(sort);
+    if (v && typeof v === "object") {
+      return Object.keys(v as Record<string, unknown>)
+        .sort()
+        .reduce<Record<string, unknown>>((o, k) => {
+          o[k] = sort((v as Record<string, unknown>)[k]);
+          return o;
+        }, {});
+    }
+    return v;
+  };
+  return sort(p);
+}
+
 /** SHA-256 of an event's canonical form (hex) — what the NEXT event chains to. */
 export function hashEvent(canonical: string): string {
   return createHash("sha256").update(canonical, "utf8").digest("hex");
@@ -71,24 +96,25 @@ export class EventLog {
   }
 
   /** Append one event to the chain. Returns the persisted row. Serialized. */
-  append(input: AppendInput): Promise<EventRow> {
+  append(input: AppendInput): Promise<LedgerEventRow> {
     const run = this.#tail.then(() => this.#appendNow(input));
     // Keep the chain going even if one append rejects (don't wedge the lock).
     this.#tail = run.catch(() => undefined);
     return run;
   }
 
-  #appendNow(input: AppendInput): EventRow {
+  #appendNow(input: AppendInput): LedgerEventRow {
     const prev = this.#db
       .select()
-      .from(events)
+      .from(ledgerEvents)
-      .orderBy(desc(events.index))
+      .orderBy(desc(ledgerEvents.index))
       .limit(1)
       .get();
 
     const index = (prev?.index ?? 0) + 1;
     const prevHash = prev ? hashEvent(canonicalize(prev)) : null;
     const occurredAt = input.occurredAt ?? new Date().toISOString();
+    const payload = input.payload ?? null;
 
     const canonical = canonicalize({
       index,
@@ -97,6 +123,7 @@ export class EventLog {
       lane: input.lane,
       source: input.source ?? null,
       identity: input.identity ?? null,
+      payload,
       occurredAt,
       prevHash,
     });
@@ -109,13 +136,15 @@ export class EventLog {
       lane: input.lane,
       source: input.source ?? null,
       identity: input.identity ?? null,
+      payload,
       occurredAt,
       prevHash,
       signature: this.#signer.sign(canonical),
+      keyId: this.#signer.keyId,
     };
 
-    this.#db.insert(events).values(row).run();
+    this.#db.insert(ledgerEvents).values(row).run();
-    return row as EventRow;
+    return row as LedgerEventRow;
   }
 
   /**
@@ -125,7 +154,7 @@ export class EventLog {
    * row (index gap), and a forged/invalid signature.
    */
   verifyChain(): { ok: true } | { ok: false; index: number; reason: string } {
-    const rows = this.#db.select().from(events).orderBy(events.index).all();
+    const rows = this.#db.select().from(ledgerEvents).orderBy(ledgerEvents.index).all();
     let expectedIndex = 1;
     let prevHash: string | null = null;
     for (const row of rows) {

apps/server/src/routes/events.ts

@@ -1,5 +1,5 @@
 import type { FastifyInstance } from "fastify";
-import { desc, events, type Db } from "@parking/db";
+import { desc, ledgerEvents, type Db } from "@parking/db";
 import { requireRole } from "../auth.js";
 import type { EventLog } from "../event-log.js";
 
@@ -22,7 +22,7 @@ export async function eventRoutes(
     { preHandler: guard },
     async (req) => {
       const limit = Math.min(Math.max(Number(req.query.limit) || 100, 1), 1000);
-      const rows = db.select().from(events).orderBy(desc(events.index)).limit(limit).all();
+      const rows = db.select().from(ledgerEvents).orderBy(desc(ledgerEvents.index)).limit(limit).all();
       return { events: rows };
     },
   );

apps/server/src/server.ts

@@ -1,7 +1,8 @@
 import cookie from "@fastify/cookie";
 import jwt from "@fastify/jwt";
 import Fastify, { type FastifyInstance } from "fastify";
-import { createDb, type Db } from "@parking/db";
+import { randomUUID } from "node:crypto";
+import { createDb, deviceEvents as deviceEventsTable, type Db } from "@parking/db";
 import { TOKEN_COOKIE, requireJwtSecret } from "./auth.js";
 import { deviceEvents } from "./device-events.js";
 import { EventLog } from "./event-log.js";
@@ -70,39 +71,41 @@ export async function buildServer(opts: BuildOptions = {}): Promise<FastifyInsta
   app.addHook("onReady", async () => printerMonitor.start());
   app.addHook("onClose", async () => printerMonitor.stop());
 
-  // Append-only signed event log. Subscribe device pushes (e.g. Dingtian button
+  // Append-only signed business LEDGER (ledger_events). Holds only business facts
-  // presses) into the hash-chained, signed `events` table — the anti-fraud audit
+  // (vehicle_entry/exit, payment, void, …) — the anti-fraud audit trail. A raw
-  // trail. The device is NOT trusted; the host record is the source of truth, and
+  // button press is NOT a business fact: it's device telemetry, recorded UNSIGNED
-  // a relay open with no matching signed event is itself the anomaly. We record
+  // in device_events. The entry flow (TODO) turns an input into a signed
-  // the raw input faithfully as `input_received` (not yet a `vehicle_entry` — that
+  // vehicle_entry once a ticket prints + the barrier is commanded.
-  // comes with the full entry flow). See wiki/concepts/append-only-event-chain.md.
+  // See wiki/decisions/event-streams-split.md.
   const eventLog = new EventLog(db, buildSigner(app.log));
   await eventRoutes(app, db, eventLog);
   const unsubscribeInput = deviceEvents.onInput((e) => {
     // Resolve which lane the device belongs to. -1 marks "device fired but isn't
     // mapped to a lane" (assigned without a lane, or a stale id) — still recorded
-    // faithfully (the chain is append-only) rather than silently dropped or
+    // faithfully rather than silently dropped or mis-stamped as lane 0 (a real lane).
-    // mis-stamped as lane 0, which is a real lane.
     const lane = laneMap.laneFor(e.deviceId) ?? -1;
     if (lane === -1) {
       app.log.warn(`input from unmapped device ${e.driverId}:${e.deviceId} — logged as lane -1`);
     }
-    eventLog
+    try {
-      .append({
+      db.insert(deviceEventsTable)
-        type: "input_received",
+        .values({
-        lane,
+          id: randomUUID(),
-        // `source` is an IdentitySource (wiegand/lpr/qr/ticket/manual) — how a
+          deviceId: e.deviceId,
-        // VEHICLE was identified. A raw input has none, so it stays null. The
+          lane,
-        // device provenance lives in `identity` instead.
+          category: "access",
-        source: null,
+          kind: "input",
-        identity: `${e.driverId}:${e.deviceId} input:${e.input}/${e.edge}`,
+          detail: { driverId: e.driverId, input: e.input, edge: e.edge },
-        occurredAt: e.at,
+          occurredAt: e.at,
-      })
+        })
-      .catch((err) => app.log.error(`event-log append failed: ${(err as Error).message}`));
+        .run();
+    } catch (err) {
+      app.log.error(`device-event insert failed: ${(err as Error).message}`);
+    }
   });
   app.addHook("onClose", async () => unsubscribeInput());
 
-  // TODO: entry flow (input event → signed event → print → relay).
+  // TODO: entry flow (device input → signed vehicle_entry → print → relay).
 
   return app;
 }

packages/db/drizzle/0000_absent_rocket_raccoon.sql

@@ -1,23 +0,0 @@
-CREATE TABLE `events` (
-	`id` text PRIMARY KEY NOT NULL,
-	`index` integer NOT NULL,
-	`type` text NOT NULL,
-	`direction` text,
-	`lane` integer NOT NULL,
-	`source` text,
-	`identity` text,
-	`occurred_at` text NOT NULL,
-	`prev_hash` text,
-	`signature` text NOT NULL
-);
---> statement-breakpoint
-CREATE UNIQUE INDEX `events_index_unique` ON `events` (`index`);--> statement-breakpoint
-CREATE TABLE `users` (
-	`id` text PRIMARY KEY NOT NULL,
-	`username` text NOT NULL,
-	`password_hash` text NOT NULL,
-	`role` text NOT NULL,
-	`created_at` text DEFAULT (current_timestamp) NOT NULL
-);
---> statement-breakpoint
-CREATE UNIQUE INDEX `users_username_unique` ON `users` (`username`);

packages/db/drizzle/0000_baseline.sql

@@ -0,0 +1,113 @@
+CREATE TABLE `blocklist` (
+	`id` text PRIMARY KEY NOT NULL,
+	`kind` text NOT NULL,
+	`value` text NOT NULL,
+	`reason` text,
+	`active` integer DEFAULT true NOT NULL,
+	`added_by` text,
+	`added_at` text DEFAULT (current_timestamp) NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE `device_events` (
+	`id` text PRIMARY KEY NOT NULL,
+	`device_id` text,
+	`lane` integer,
+	`category` text,
+	`kind` text NOT NULL,
+	`detail` text,
+	`occurred_at` text DEFAULT (current_timestamp) NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE `lane_devices` (
+	`id` text PRIMARY KEY NOT NULL,
+	`lane` integer NOT NULL,
+	`category` text NOT NULL,
+	`driver_id` text NOT NULL,
+	`config` text NOT NULL,
+	`enabled` integer DEFAULT true NOT NULL,
+	`created_at` text DEFAULT (current_timestamp) NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE `ledger_events` (
+	`id` text PRIMARY KEY NOT NULL,
+	`index` integer NOT NULL,
+	`type` text NOT NULL,
+	`direction` text,
+	`lane` integer NOT NULL,
+	`source` text,
+	`identity` text,
+	`payload` text,
+	`occurred_at` text NOT NULL,
+	`prev_hash` text,
+	`signature` text NOT NULL,
+	`key_id` text NOT NULL
+);
+--> statement-breakpoint
+CREATE UNIQUE INDEX `ledger_events_index_unique` ON `ledger_events` (`index`);--> statement-breakpoint
+CREATE TABLE `permit_credentials` (
+	`id` text PRIMARY KEY NOT NULL,
+	`permit_id` text NOT NULL,
+	`kind` text NOT NULL,
+	`value` text NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE `permit_plates` (
+	`id` text PRIMARY KEY NOT NULL,
+	`permit_id` text NOT NULL,
+	`plate` text NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE `permits` (
+	`id` text PRIMARY KEY NOT NULL,
+	`holder_name` text,
+	`contact` text,
+	`max_concurrent` integer DEFAULT 1,
+	`valid_from` text,
+	`valid_to` text,
+	`status` text DEFAULT 'active' NOT NULL,
+	`created_at` text DEFAULT (current_timestamp) NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE `sessions` (
+	`id` text PRIMARY KEY NOT NULL,
+	`lane` integer,
+	`identity` text,
+	`source` text,
+	`permit_id` text,
+	`entered_at` text NOT NULL,
+	`exited_at` text,
+	`state` text DEFAULT 'open' NOT NULL,
+	`last_event_index` integer
+);
+--> statement-breakpoint
+CREATE TABLE `setup_state` (
+	`id` integer PRIMARY KEY NOT NULL,
+	`completed_at` text
+);
+--> statement-breakpoint
+CREATE TABLE `tariff_versions` (
+	`id` text PRIMARY KEY NOT NULL,
+	`tariff_id` text NOT NULL,
+	`effective_from` text NOT NULL,
+	`currency` text NOT NULL,
+	`structure` text NOT NULL,
+	`created_by` text,
+	`created_at` text DEFAULT (current_timestamp) NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE `tariffs` (
+	`id` text PRIMARY KEY NOT NULL,
+	`scope` text DEFAULT 'site' NOT NULL,
+	`name` text NOT NULL,
+	`created_at` text DEFAULT (current_timestamp) NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE `users` (
+	`id` text PRIMARY KEY NOT NULL,
+	`username` text NOT NULL,
+	`password_hash` text NOT NULL,
+	`role` text NOT NULL,
+	`created_at` text DEFAULT (current_timestamp) NOT NULL
+);
+--> statement-breakpoint
+CREATE UNIQUE INDEX `users_username_unique` ON `users` (`username`);

packages/db/drizzle/0001_cuddly_maria_hill.sql

@@ -1,14 +0,0 @@
-CREATE TABLE `lane_devices` (
-	`id` text PRIMARY KEY NOT NULL,
-	`lane` integer NOT NULL,
-	`category` text NOT NULL,
-	`driver_id` text NOT NULL,
-	`config` text NOT NULL,
-	`enabled` integer DEFAULT true NOT NULL,
-	`created_at` text DEFAULT (current_timestamp) NOT NULL
-);
---> statement-breakpoint
-CREATE TABLE `setup_state` (
-	`id` integer PRIMARY KEY NOT NULL,
-	`completed_at` text
-);

packages/db/drizzle/meta/0000_snapshot.json

@@ -1,11 +1,193 @@
 {
   "version": "6",
   "dialect": "sqlite",
-  "id": "721bbb8f-b929-4018-9420-0ae75b03ff93",
+  "id": "cd09c11f-4306-4ac8-a335-7c050d080ab6",
   "prevId": "00000000-0000-0000-0000-000000000000",
   "tables": {
-    "events": {
+    "blocklist": {
-      "name": "events",
+      "name": "blocklist",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "kind": {
+          "name": "kind",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "value": {
+          "name": "value",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "reason": {
+          "name": "reason",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "active": {
+          "name": "active",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": true
+        },
+        "added_by": {
+          "name": "added_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "added_at": {
+          "name": "added_at",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": "(current_timestamp)"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
+    "device_events": {
+      "name": "device_events",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "device_id": {
+          "name": "device_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "lane": {
+          "name": "lane",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "category": {
+          "name": "category",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "kind": {
+          "name": "kind",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "detail": {
+          "name": "detail",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "occurred_at": {
+          "name": "occurred_at",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": "(current_timestamp)"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
+    "lane_devices": {
+      "name": "lane_devices",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "lane": {
+          "name": "lane",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "category": {
+          "name": "category",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "driver_id": {
+          "name": "driver_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "config": {
+          "name": "config",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "enabled": {
+          "name": "enabled",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": true
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": "(current_timestamp)"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
+    "ledger_events": {
+      "name": "ledger_events",
       "columns": {
         "id": {
           "name": "id",
@@ -56,6 +238,13 @@
           "notNull": false,
           "autoincrement": false
         },
+        "payload": {
+          "name": "payload",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
         "occurred_at": {
           "name": "occurred_at",
           "type": "text",
@@ -76,11 +265,18 @@
           "primaryKey": false,
           "notNull": true,
           "autoincrement": false
+        },
+        "key_id": {
+          "name": "key_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
         }
       },
       "indexes": {
-        "events_index_unique": {
+        "ledger_events_index_unique": {
-          "name": "events_index_unique",
+          "name": "ledger_events_index_unique",
           "columns": [
             "index"
           ],
@@ -92,6 +288,342 @@
       "uniqueConstraints": {},
       "checkConstraints": {}
     },
+    "permit_credentials": {
+      "name": "permit_credentials",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "permit_id": {
+          "name": "permit_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "kind": {
+          "name": "kind",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "value": {
+          "name": "value",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
+    "permit_plates": {
+      "name": "permit_plates",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "permit_id": {
+          "name": "permit_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "plate": {
+          "name": "plate",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
+    "permits": {
+      "name": "permits",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "holder_name": {
+          "name": "holder_name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "contact": {
+          "name": "contact",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "max_concurrent": {
+          "name": "max_concurrent",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false,
+          "default": 1
+        },
+        "valid_from": {
+          "name": "valid_from",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "valid_to": {
+          "name": "valid_to",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "status": {
+          "name": "status",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": "'active'"
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": "(current_timestamp)"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
+    "sessions": {
+      "name": "sessions",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "lane": {
+          "name": "lane",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "identity": {
+          "name": "identity",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "source": {
+          "name": "source",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "permit_id": {
+          "name": "permit_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "entered_at": {
+          "name": "entered_at",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "exited_at": {
+          "name": "exited_at",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "state": {
+          "name": "state",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": "'open'"
+        },
+        "last_event_index": {
+          "name": "last_event_index",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
+    "setup_state": {
+      "name": "setup_state",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "integer",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "completed_at": {
+          "name": "completed_at",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
+    "tariff_versions": {
+      "name": "tariff_versions",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "tariff_id": {
+          "name": "tariff_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "effective_from": {
+          "name": "effective_from",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "currency": {
+          "name": "currency",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "structure": {
+          "name": "structure",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "created_by": {
+          "name": "created_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": "(current_timestamp)"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
+    "tariffs": {
+      "name": "tariffs",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "scope": {
+          "name": "scope",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": "'site'"
+        },
+        "name": {
+          "name": "name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false,
+          "default": "(current_timestamp)"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "checkConstraints": {}
+    },
     "users": {
       "name": "users",
       "columns": {

packages/db/drizzle/meta/0001_snapshot.json

@@ -1,245 +0,0 @@
-{
-  "version": "6",
-  "dialect": "sqlite",
-  "id": "1073123c-0df9-4109-84bf-7f23b95ec5bd",
-  "prevId": "721bbb8f-b929-4018-9420-0ae75b03ff93",
-  "tables": {
-    "events": {
-      "name": "events",
-      "columns": {
-        "id": {
-          "name": "id",
-          "type": "text",
-          "primaryKey": true,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "index": {
-          "name": "index",
-          "type": "integer",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "type": {
-          "name": "type",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "direction": {
-          "name": "direction",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": false,
-          "autoincrement": false
-        },
-        "lane": {
-          "name": "lane",
-          "type": "integer",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "source": {
-          "name": "source",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": false,
-          "autoincrement": false
-        },
-        "identity": {
-          "name": "identity",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": false,
-          "autoincrement": false
-        },
-        "occurred_at": {
-          "name": "occurred_at",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "prev_hash": {
-          "name": "prev_hash",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": false,
-          "autoincrement": false
-        },
-        "signature": {
-          "name": "signature",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        }
-      },
-      "indexes": {
-        "events_index_unique": {
-          "name": "events_index_unique",
-          "columns": [
-            "index"
-          ],
-          "isUnique": true
-        }
-      },
-      "foreignKeys": {},
-      "compositePrimaryKeys": {},
-      "uniqueConstraints": {},
-      "checkConstraints": {}
-    },
-    "lane_devices": {
-      "name": "lane_devices",
-      "columns": {
-        "id": {
-          "name": "id",
-          "type": "text",
-          "primaryKey": true,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "lane": {
-          "name": "lane",
-          "type": "integer",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "category": {
-          "name": "category",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "driver_id": {
-          "name": "driver_id",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "config": {
-          "name": "config",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "enabled": {
-          "name": "enabled",
-          "type": "integer",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false,
-          "default": true
-        },
-        "created_at": {
-          "name": "created_at",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false,
-          "default": "(current_timestamp)"
-        }
-      },
-      "indexes": {},
-      "foreignKeys": {},
-      "compositePrimaryKeys": {},
-      "uniqueConstraints": {},
-      "checkConstraints": {}
-    },
-    "setup_state": {
-      "name": "setup_state",
-      "columns": {
-        "id": {
-          "name": "id",
-          "type": "integer",
-          "primaryKey": true,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "completed_at": {
-          "name": "completed_at",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": false,
-          "autoincrement": false
-        }
-      },
-      "indexes": {},
-      "foreignKeys": {},
-      "compositePrimaryKeys": {},
-      "uniqueConstraints": {},
-      "checkConstraints": {}
-    },
-    "users": {
-      "name": "users",
-      "columns": {
-        "id": {
-          "name": "id",
-          "type": "text",
-          "primaryKey": true,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "username": {
-          "name": "username",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "password_hash": {
-          "name": "password_hash",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "role": {
-          "name": "role",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false
-        },
-        "created_at": {
-          "name": "created_at",
-          "type": "text",
-          "primaryKey": false,
-          "notNull": true,
-          "autoincrement": false,
-          "default": "(current_timestamp)"
-        }
-      },
-      "indexes": {
-        "users_username_unique": {
-          "name": "users_username_unique",
-          "columns": [
-            "username"
-          ],
-          "isUnique": true
-        }
-      },
-      "foreignKeys": {},
-      "compositePrimaryKeys": {},
-      "uniqueConstraints": {},
-      "checkConstraints": {}
-    }
-  },
-  "views": {},
-  "enums": {},
-  "_meta": {
-    "schemas": {},
-    "tables": {},
-    "columns": {}
-  },
-  "internal": {
-    "indexes": {}
-  }
-}

packages/db/drizzle/meta/_journal.json

@@ -5,15 +5,8 @@
     {
       "idx": 0,
       "version": "6",
-      "when": 1781389618205,
+      "when": 1781539958008,
-      "tag": "0000_absent_rocket_raccoon",
+      "tag": "0000_baseline",
-      "breakpoints": true
-    },
-    {
-      "idx": 1,
-      "version": "6",
-      "when": 1781416636098,
-      "tag": "0001_cuddly_maria_hill",
       "breakpoints": true
     }
   ]

packages/db/src/schema.ts

@@ -2,10 +2,16 @@ import { sql } from "drizzle-orm";
 import { integer, sqliteTable, text } from "drizzle-orm/sqlite-core";
 
 // Schema notes:
-// - `events` is APPEND-ONLY. Never expose UPDATE/DELETE on it. A correction or
+// - TWO event streams, deliberately separate (see wiki/decisions/event-streams-split.md):
-//   void is a new row of type 'void'. Each row chains to the previous via
+//     • `ledger_events` — the APPEND-ONLY, hash-chained, ATECC608-SIGNED business ledger.
-//   `prevHash` and is signed by the ATECC608 (`signature`). This is the core
+//       Never UPDATE/DELETE. A correction or void is a new row of type 'void'. Each row
-//   anti-fraud integrity mechanism. See wiki/concepts/append-only-event-chain.md.
+//       chains via `prevHash` and is signed (`signature`). The anti-fraud record; sessions,
+//       tariffs and occupancy are PROJECTIONS over it. See append-only-event-chain.md.
+//     • `device_events` — UNSIGNED operational telemetry (relay/printer/camera/reader/input).
+//       High-volume, prunable, never reconciled. See wiki/concepts/device-events.md.
+// - Business master data (tariffs/permits/blocklist) IS mutable, but its USE is fixed in a
+//   signed ledger event, so the audit trail stays append-only. Tariffs are versioned:
+//   editing publishes a new immutable tariff_version. See wiki/concepts/tariff.md.
 // - `users` holds bcrypt hashes + a role; auth is fully local (offline-first).
 //   See wiki/entities/local-jwt-auth.md.
 
@@ -21,7 +27,13 @@ export const users = sqliteTable("users", {
     .default(sql`(current_timestamp)`),
 });
 
-export const events = sqliteTable("events", {
+// --- The signed business ledger (formerly `events`) ----------------------
+// Holds ONLY business/accountability facts: vehicle_entry, vehicle_exit, payment,
+// void, shift_z_report, plus witness-grade barrier_open_command/observed, anomaly.
+// `payload` carries type-specific data (amount, tariffVersionId, sessionRef, tender,
+// plate confidence…) and is part of the SIGNED canonical form, so it is tamper-evident
+// like the rest of the row. See packages/shared ParkingEventType + LedgerPayload.
+export const ledgerEvents = sqliteTable("ledger_events", {
   id: text("id").primaryKey(),
   // Monotonic chain index. Gaps are alarms (see event-log-ingestion).
   index: integer("index").notNull().unique(),
@@ -30,18 +42,43 @@ export const events = sqliteTable("events", {
   lane: integer("lane").notNull(),
   source: text("source"),
   identity: text("identity"),
+  // Type-specific business payload (JSON). Signed as part of the canonical form.
+  payload: text("payload", { mode: "json" }).$type<Record<string, unknown>>(),
   occurredAt: text("occurred_at").notNull(),
   // Hash of the previous event (hex). Null only for the genesis event.
   prevHash: text("prev_hash"),
   // ATECC608 signature over the canonical event payload (hex).
   signature: text("signature").notNull(),
+  // Which signer/key produced `signature` (e.g. "sw-hmac-v1", "atecc608-slot0"),
+  // so old events stay verifiable across a signer swap. See packages/shared Signer.
+  keyId: text("key_id").notNull(),
 });
 
-// Per-lane device assignments chosen by the admin during first-run setup.
+// --- Device telemetry (unsigned, prunable) -------------------------------
+// Operational monitoring, NOT anti-fraud: relay fired, printer paper-out, camera
+// offline, reader read, raw input edges. Keyed to a lane_devices instance; lane is
+// resolved via the LaneMap. No prevHash/signature — this stream may rotate/prune.
+export const deviceEvents = sqliteTable("device_events", {
+  id: text("id").primaryKey(),
+  // The lane_devices instance that produced it (raw provenance).
+  deviceId: text("device_id"),
+  lane: integer("lane"),
+  category: text("category", {
+    enum: ["access", "reader", "camera", "printer"],
+  }),
+  // e.g. "input", "relay", "status", "read", "snapshot".
+  kind: text("kind").notNull(),
+  // Free-form telemetry detail (input number + edge, status flags, error…).
+  detail: text("detail", { mode: "json" }).$type<Record<string, unknown>>(),
+  occurredAt: text("occurred_at")
+    .notNull()
+    .default(sql`(current_timestamp)`),
+});
+
+// --- Per-lane device assignments (first-run setup) -----------------------
 // One row per (lane, category, instance). `driverId` references a driver in the
-// @parking/devices registry; `config` is that driver's JSON config (host, port,
+// @parking/devices registry; `config` is that driver's JSON config. Keeps the
-// credentials…). Lets the system stay device-agnostic and admin-configurable.
+// system device-agnostic + admin-configurable. See device-registry.md, first-run-setup.md.
-// See wiki/concepts/device-registry.md and first-run-setup.md.
 export const laneDevices = sqliteTable("lane_devices", {
   id: text("id").primaryKey(),
   lane: integer("lane").notNull(),
@@ -64,7 +101,124 @@ export const setupState = sqliteTable("setup_state", {
   completedAt: text("completed_at"),
 });
 
+// --- Tariffs (composable, versioned) -------------------------------------
+// A `tariffs` row is a logical rate card; its pricing lives in immutable, effective-
+// dated `tariff_versions`. Editing prices PUBLISHES a new version, never mutates one.
+// A session reprices against the version in force at its entry time; the `payment`
+// ledger event records the tariffVersionId used. "One active tariff per site" today;
+// `scope` lets multiple be added later without migration. See wiki/concepts/tariff.md.
+export const tariffs = sqliteTable("tariffs", {
+  id: text("id").primaryKey(),
+  // Only "site" used now; "lane"/"zone" reserved for multi-tariff later.
+  scope: text("scope", { enum: ["site", "lane", "zone"] }).notNull().default("site"),
+  name: text("name").notNull(),
+  createdAt: text("created_at")
+    .notNull()
+    .default(sql`(current_timestamp)`),
+});
+
+export const tariffVersions = sqliteTable("tariff_versions", {
+  id: text("id").primaryKey(),
+  tariffId: text("tariff_id").notNull(),
+  // The version is in force from this instant (latest with effectiveFrom ≤ entry wins).
+  effectiveFrom: text("effective_from").notNull(),
+  // ISO 4217; selectable. Money everywhere is { minorUnits, currency }, never a float.
+  currency: text("currency").notNull(),
+  // The composable rate card (stepped blocks + caps/grace). Shape: TariffStructure
+  // in packages/shared. Immutable once published.
+  structure: text("structure", { mode: "json" }).notNull().$type<Record<string, unknown>>(),
+  createdBy: text("created_by"),
+  createdAt: text("created_at")
+    .notNull()
+    .default(sql`(current_timestamp)`),
+});
+
+// --- Permits (subscriptions) ---------------------------------------------
+// Mutable master data; every USE produces a signed vehicle_entry/exit ledger event.
+// Two optional, independent bindings: car-count (maxConcurrent, default 1, null =
+// unbound) and plate (plates rows, default none = any car). Identity = card/QR OR a
+// matching plate. Credentials and cars are child rows. See wiki/entities/permit.md.
+export const permits = sqliteTable("permits", {
+  id: text("id").primaryKey(),
+  holderName: text("holder_name"),
+  contact: text("contact"),
+  // Car-count binding: how many of the permit's cars may be inside at once.
+  // null = unbound. Default 1.
+  maxConcurrent: integer("max_concurrent").default(1),
+  validFrom: text("valid_from"),
+  validTo: text("valid_to"),
+  status: text("status", { enum: ["active", "suspended", "revoked"] })
+    .notNull()
+    .default("active"),
+  createdAt: text("created_at")
+    .notNull()
+    .default(sql`(current_timestamp)`),
+});
+
+// A permit's credentials (RF tag/chip/card, or QR). Either opens the lane.
+export const permitCredentials = sqliteTable("permit_credentials", {
+  id: text("id").primaryKey(),
+  permitId: text("permit_id").notNull(),
+  kind: text("kind", { enum: ["rf", "qr"] }).notNull(),
+  value: text("value").notNull(),
+});
+
+// Plate binding (optional). When a permit has plate rows, a matching plate read is
+// itself an accepted identity (card/QR OR plate). Empty = not plate-bound (any car).
+export const permitPlates = sqliteTable("permit_plates", {
+  id: text("id").primaryKey(),
+  permitId: text("permit_id").notNull(),
+  plate: text("plate").notNull(),
+});
+
+// --- Blocklist (banlist) -------------------------------------------------
+// Plates/cards refused at ENTRY (never at exit — never trap a vehicle). A hit appends
+// a signed anomaly/refused-entry ledger event. See wiki/entities/blocklist.md.
+export const blocklist = sqliteTable("blocklist", {
+  id: text("id").primaryKey(),
+  kind: text("kind", { enum: ["plate", "card", "qr"] }).notNull(),
+  value: text("value").notNull(),
+  reason: text("reason"),
+  active: integer("active", { mode: "boolean" }).notNull().default(true),
+  addedBy: text("added_by"),
+  addedAt: text("added_at")
+    .notNull()
+    .default(sql`(current_timestamp)`),
+});
+
+// --- Sessions (PROJECTION cache) -----------------------------------------
+// NOT a source of truth — a rebuildable fold over ledger_events for fast queries
+// (occupancy, pay-station lookup, anti-passback, plate search). Always reconstructable
+// from the signed chain; never the authority for "paid". See wiki/concepts/parking-session.md.
+export const sessions = sqliteTable("sessions", {
+  // The session key = the entry's identity (ticket id or plate).
+  id: text("id").primaryKey(),
+  lane: integer("lane"),
+  // Identity that opened the session, and how it was read.
+  identity: text("identity"),
+  source: text("source"),
+  // null while transient; set when matched to a permit.
+  permitId: text("permit_id"),
+  enteredAt: text("entered_at").notNull(),
+  // null until exit; presence = CLOSED.
+  exitedAt: text("exited_at"),
+  // Derived state for quick filtering: open | paid | closed | voided.
+  state: text("state", { enum: ["open", "paid", "closed", "voided"] })
+    .notNull()
+    .default("open"),
+  // Index of the last ledger event folded into this row (cache freshness / rebuild).
+  lastEventIndex: integer("last_event_index"),
+});
+
 export type UserRow = typeof users.$inferSelect;
-export type EventRow = typeof events.$inferSelect;
+export type LedgerEventRow = typeof ledgerEvents.$inferSelect;
+export type DeviceEventRow = typeof deviceEvents.$inferSelect;
 export type LaneDeviceRow = typeof laneDevices.$inferSelect;
 export type SetupStateRow = typeof setupState.$inferSelect;
+export type TariffRow = typeof tariffs.$inferSelect;
+export type TariffVersionRow = typeof tariffVersions.$inferSelect;
+export type PermitRow = typeof permits.$inferSelect;
+export type PermitCredentialRow = typeof permitCredentials.$inferSelect;
+export type PermitPlateRow = typeof permitPlates.$inferSelect;
+export type BlocklistRow = typeof blocklist.$inferSelect;
+export type SessionRow = typeof sessions.$inferSelect;

packages/shared/src/index.ts

@@ -13,39 +13,106 @@ export type Direction = "entry" | "exit";
 export type IdentitySource = "wiegand" | "lpr" | "qr" | "ticket" | "manual";
 
 /**
- * An append-only parking event. Records are never mutated; corrections are new
+ * A signed business-LEDGER event. Records are never mutated; corrections are new
  * events. `prevHash` chains each event to the previous one; `signature` is the
- * ATECC608 signature over the event contents. See wiki/append-only-event-chain.
+ * ATECC608 signature over the canonical contents (which INCLUDE `payload`).
+ * Distinct from device telemetry — see wiki/decisions/event-streams-split.md.
  */
-export interface ParkingEvent {
+export interface LedgerEvent {
   readonly id: string;
   readonly index: number;
-  readonly type: ParkingEventType;
+  readonly type: LedgerEventType;
   readonly direction: Direction | null;
   readonly lane: number;
   readonly source: IdentitySource | null;
   /** Card number, plate, ticket id, etc. — depends on `source`. */
   readonly identity: string | null;
+  /** Type-specific business data (amount, tariffVersionId, sessionRef…). Signed. */
+  readonly payload: LedgerPayload | null;
   readonly occurredAt: string; // ISO-8601
   /** Hash of the previous event in the chain (hex). Null only for genesis. */
   readonly prevHash: string | null;
   /** ATECC608 signature over the canonical event payload (hex). */
   readonly signature: string;
+  /** Which signer/key produced `signature` (verifiable across a signer swap). */
+  readonly keyId: string;
 }
 
-export type ParkingEventType =
+/** Business/accountability events that live in the SIGNED, hash-chained ledger. */
-  // A raw device input (e.g. a Dingtian button press) was received and recorded.
+export type LedgerEventType =
-  // NOT a confirmed entry — the richer `vehicle_entry` is appended later by the
-  // entry flow once a ticket prints and the barrier is commanded.
-  | "input_received"
   | "vehicle_entry"
   | "vehicle_exit"
+  | "payment"
   | "void"
+  // Witness-grade: a host-commanded open, and an independently-observed open
+  // (loop/sensor) — reconciled against each other.
   | "barrier_open_command"
   | "barrier_open_observed"
   | "shift_z_report"
   | "anomaly";
 
+/** How money was tendered (for payment events + the shift Z-report). */
+export type Tender = "cash" | "card";
+
+/**
+ * Type-specific data carried on a ledger event's `payload`. All amounts are
+ * integer minor units in the named currency — never floats. Fields are optional
+ * because they're event-type-specific; the producer fills what applies.
+ */
+export interface LedgerPayload {
+  /** The parking_session this event concerns (entry/exit/payment/void). */
+  readonly sessionRef?: string;
+  /** payment: amount in minor units, its currency, and how it was tendered. */
+  readonly amountMinor?: number;
+  readonly currency?: string;
+  readonly tender?: Tender;
+  /** payment: which tariff_version priced it (reproducible repricing). */
+  readonly tariffVersionId?: string;
+  /** payment: gross/discount/net split when a validation applied. */
+  readonly grossMinor?: number;
+  readonly discountMinor?: number;
+  /** FX-ready, deferred: rate applied (null/absent now). See open-questions #8. */
+  readonly fxRate?: number | null;
+  /** void / anomaly / override: a human/machine reason code. */
+  readonly reason?: string;
+  /** plate/vehicle from the vision service (advisory). */
+  readonly plate?: string;
+  readonly plateConfidence?: number;
+  /** Free-form for forward-compat without a schema change. */
+  readonly [k: string]: unknown;
+}
+
+/** Operational device telemetry — UNSIGNED, prunable. NOT the ledger. */
+export type DeviceEventKind = "input" | "relay" | "status" | "read" | "snapshot";
+
+/**
+ * The composable rate card stored in a tariff_version.structure. Pure data the
+ * fee function interprets — no rates in code. Stepped duration blocks + caps/grace;
+ * a flat rate is just one block. See wiki/concepts/tariff.md.
+ */
+export interface TariffStructure {
+  /** Free if exited within this (drop-off/turnaround). */
+  readonly gracePeriodEntryMin: number;
+  /** Billing granularity; partial increments round UP. */
+  readonly incrementMin: number;
+  /** Consumed in order as duration accrues; last block may be open-ended. */
+  readonly blocks: readonly TariffBlock[];
+  /** Cap per rolling 24h (null = no cap). */
+  readonly dailyCapMinor: number | null;
+  /** Flat charge when there's no entry id (admin may override at the moment). */
+  readonly lostTicketMinor: number;
+  /** Pay-on-foot walk-back window: minutes after payment to reach the car. */
+  readonly gracePeriodExitMin: number;
+  /** How an overstay top-up is charged. "reprice" = recompute(entry→now) − paid. */
+  readonly overstay: "reprice";
+}
+
+export interface TariffBlock {
+  /** Upper bound of this block in minutes; null = open-ended (thereafter). */
+  readonly uptoMin: number | null;
+  readonly priceMinorPerIncrement: number;
+}
+
 export const ROLES: readonly Role[] = [
   "admin",
   "operator",

wiki/concepts/anti-passback.md

@@ -0,0 +1,57 @@
+---
+type: concept
+tags: [parking, domain, business, anti-fraud, access-control]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Anti-Passback
+
+Stop one credential/ticket from getting **two cars in** without an exit between — the classic
+"pass the card/ticket back over the fence" abuse. A control on the entry validation, leaning on the
+session projection.
+
+## The rule
+
+An identity (ticket id, [[permit]] credential, or plate) **must not enter while it already has an
+OPEN [[parking-session|session]].** At entry:
+
+```
+identify vehicle → is there already an OPEN session for this id?
+   no  → proceed (mint vehicle_entry, open)
+   yes → passback violation → refuse or flag (see policy)
+```
+
+This is a **fold over the signed [[append-only-event-chain]]** ("does an entry for this id exist
+with no matching exit?") — not a mutable in/out flag that could be edited. Same projection that
+powers [[capacity-occupancy]] and [[permit]] `maxConcurrent`.
+
+## Interaction with the limits already designed
+
+- **Transient ticket** — a single ticket id is inherently one session; a second entry on the same
+  id is always a violation (or a re-print/duplication attempt).
+- **Permit** — passback is the *per-car* case of the permit's `maxConcurrent` ([[permit]]): a
+  multi-car permit legitimately has several open sessions, but **the same car/credential** entering
+  twice is still a violation. So enforce per-identity, *under* the permit's concurrency allowance.
+
+## Policy (operator choice)
+
+- **Hard** — refuse the second entry (strict; risks stranding a legitimate car after a *missed
+  exit*, which is common — tailgated out, sensor missed).
+- **Soft** — allow but **flag an `anomaly`** (the type exists) for review. Safer against
+  false-positives from missed exits, consistent with the append-only "record + flag, don't block"
+  ethos elsewhere.
+- Likely **soft by default**, hard as an opt-in for high-control sites.
+
+## Honest limits
+
+- Depends on **reliable exit detection** — if exits are routinely missed (no exit loop/plate read),
+  passback produces false positives; tune to the site's exit fidelity.
+- A spoofed/duplicated ticket QR is caught here (same id already open) — complements
+  [[ticket-encoding]]'s opaque-id requirement.
+
+## Open
+
+- Default policy (soft/hard) and per-site override.
+- Grace for legitimate quick re-entry vs. the missed-exit false-positive.

wiki/concepts/append-only-event-chain.md

@@ -21,9 +21,25 @@ Three layered properties:
    self-consistent — someone who owns the machine still cannot forge a valid entry.
 
 It only becomes trustworthy as an external fraud control when paired with [[reconciliation]]
-against an authority the operator can't alter. Every device event — including those ingested
+against an authority the operator can't alter.
-from the [[uhppote-controller]] via [[event-log-ingestion]] — should land in this host-side
+
-chain.
+## Two event streams — the signed ledger vs. device telemetry (decision 2026-06-15)
+
+These are **different concerns and live in different tables**:
+
+- **`ledger_events`** — this signed, hash-chained, [[atecc608]]-signed **business ledger**:
+  `vehicle_entry` / `vehicle_exit` / `payment` / `void` / `shift_z_report`, plus the witness-grade
+  `barrier_open_command` / `barrier_open_observed` and `anomaly`. This is the anti-fraud record that
+  [[reconciliation]] runs against; sessions/[[tariff]]/occupancy are projections over it. (This is
+  the table formerly called `events`.)
+- **`device_events`** — **unsigned operational telemetry**: relay fired, printer paper-out, camera
+  offline, reader read, raw input edges. High-volume, churny, **not** anti-fraud; may rotate/prune.
+  Keeping it out of the signed chain keeps the ledger small and high-value.
+
+> A raw button press is **device telemetry**, not a business fact. It lands in `device_events`; the
+> entry flow then mints a **signed `vehicle_entry`** in the ledger once a ticket prints and the
+> barrier is commanded. (This supersedes the earlier "every device event lands in the chain" framing
+> and the `input_received`-as-signed-event approach — see [[device-input-flow]].)
 
 ## Implementation (apps/server)
 
@@ -58,22 +74,31 @@ so old events stay verifiable.
 > *accidental* corruption, but an operator with the signing key + DB access could re-sign a
 > forged chain. This is the central reason #6 matters.
 
-### What currently feeds the log
+### Business-layer event types (the ledger)
 
-Dingtian **input (button) pushes** → bus → `input_received` events (see [[device-input-flow]],
+The [[parking-session]] domain folds over these **signed ledger** events:
-[[dingtian-relay]]). These are recorded faithfully as raw inputs, **not** as `vehicle_entry` —
-the richer entry event waits for the entry flow (ticket print + barrier command).
 
-- **`lane`** is now resolved from the firing device. A `LaneMap` (`apps/server/src/lane-map.ts`)
+- `vehicle_entry` / `vehicle_exit` — a stay's endpoints; `identity` carries the ticket id or plate.
-  caches `lane_devices.id → lane`, built at startup and refreshed by the setup routes on every
+- `payment` — a settled fee at the pay station, referencing the session it pays for (amount in
-  assign/unassign. Device events carry the device instance id, not a lane; the handler looks it
+  integer minor units; see [[tariff]]). Making "paid" a signed event — not a mutable row — is the
-  up. A device with no mapping (assigned without a lane, or a stale id) logs **`lane: -1`** and a
+  whole point: an operator can't forge it or silently delete it.
-  warning — never `0`, which is a real lane — and is still recorded (the chain is append-only;
+- `void` — a correction / lost-ticket write-off; like every other void here it is an **appended
-  nothing is dropped).
+  event, never an erasure**.
-- **`source` stays `null`** for `input_received`, and deliberately so: `source` is an
+- `shift_z_report` — the signed per-[[shift]] takings summary.
-  `IdentitySource` (`wiegand | lpr | qr | ticket | manual`) — *how a vehicle was identified* — not
+
-  a device/IP field. A raw button push has no vehicle identity. The device provenance lives in
+A session is a **projection** over this chain, never a mutable table — the same anti-fraud reason
-  **`identity`** (e.g. `dingtian:<id> input:1/on`).
+the chain exists. See [[parking-session]].
+
+### ⚠️ As-built vs. the table split (pending)
+
+The current code records Dingtian **input (button) pushes** as `input_received` rows **in the
+signed chain** (with `lane` resolved via the `LaneMap`, `source` null, device provenance in
+`identity`). Per the 2026-06-15 split (above), a raw button press is **device telemetry** and
+belongs in **`device_events`**, *not* the signed ledger — only the business `vehicle_entry` it
+drives gets signed. So `input_received`-in-the-ledger is **transitional**; the pending refactor
+moves raw inputs to `device_events` and renames the chain table to `ledger_events`. (`LaneMap`
+lane-resolution and the "never stamp `lane: 0` for an unmapped device" rule carry over to whichever
+stream records the event.)
 
 ### ⚠️ Limitation: the log captures HOST-ORIGINATED actions only
 
@@ -91,7 +116,9 @@ host. **Proven on hardware**: a binary relay command sent directly to the device
 So the log alone does **not** detect operator/attacker fraud at the relay. That is **by design** —
 the actual control is [[reconciliation]]: compare the host's signed *commanded* opens against an
 **independent witness** of opens that physically happened (a door/loop sensor on a Dingtian input
-→ which DOES push + log; the [[lpr-camera]]; payment/Z-report). **A physical open with no matching
+→ which DOES push + log; the [[opencv-anpr-service|vision service]]'s plate **and vehicle** read;
-signed command is the fraud signal.** Both the witness sources and the reconciliation logic are
+payment/Z-report). **A physical open with no matching signed command is the fraud signal** — and,
-**NOT yet built** — this is the main open gap. Prevention (VLAN isolation so the attacker can't
+with vehicle verification, **a plate that enters/exits on a different car** is too (the
+plate-spoofing case). Both the witness sources and the reconciliation logic are **NOT yet built** —
+this is the main open gap. Prevention (VLAN isolation so the attacker can't
 reach UDP 60000) is the necessary first line; detection-via-reconciliation is the backstop.

wiki/concepts/capacity-occupancy.md

@@ -0,0 +1,40 @@
+---
+type: concept
+tags: [parking, domain, business, occupancy]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Capacity & Occupancy
+
+How many vehicles are inside, how many spaces remain, and what happens when the lot is full.
+
+## Occupancy is a projection (like everything else)
+
+`occupancy = count(open [[parking-session|sessions]])` — an entry with no matching exit. It is a
+**fold over the signed [[append-only-event-chain]]**, never a hand-maintained counter (a counter is
+editable and drifts; the chain is the truth). Spaces-free = `capacity − occupancy`.
+
+- **`capacity`** is admin-set per site (and per **zone/level** if the lot has sections — model a
+  `zone` on capacity + on the entry so multi-level is a later addition, not a rewrite).
+- Permit concurrency (`maxConcurrent`, see [[permit]]) is the same kind of fold, scoped to one
+  permit's open sessions.
+
+## Full → refuse entry + FULL sign
+
+- When `occupancy ≥ capacity`, the entry flow **refuses** (no `vehicle_entry`, no barrier open) and
+  can drive a **"FULL" sign** (a relay/output, via the device adapter layer).
+- **Safety/policy nuance:** "full" blocks *entry* only — **exit always works** ([[fail-state-safety]]:
+  exit fails open; never trap a vehicle). Permit holders may be allowed in past a "transient full"
+  threshold (reserve spaces for subscribers) — an optional policy knob.
+- **Counting drift is real:** tailgating (two cars, one entry) and missed reads make the live count
+  diverge from physical reality. The count is the *system's* occupancy; periodic ground-truth (a
+  loop count, or the [[opencv-anpr-service|vision]] count) reconciles it — surfaced as an anomaly,
+  not silently corrected.
+
+## Open
+
+- Whether "FULL" is a hard block or a soft warning (operator can wave one in) — operator policy.
+- Zone/level granularity at launch vs. single capacity number.
+- Reserve-for-permits threshold.

wiki/concepts/clock-integrity.md

@@ -0,0 +1,48 @@
+---
+type: concept
+tags: [parking, security, integrity, offline-first, anti-fraud]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Clock Integrity
+
+Fees are a function of **time** ([[tariff]]: `fee = f(enteredAt, asOf)`), and the event chain is
+ordered/timestamped. So **the host clock is part of the trust model** — and on an offline appliance
+([[offline-first]], no NTP guarantee) it's a real attack surface, fitting the
+[[threat-model|operator-as-adversary]] frame:
+
+- **Backdating to cut a fee** — wind the clock back so a long stay computes as short, or so an exit
+  timestamps before its entry.
+- **Forward/backward jumps** that corrupt durations, the rolling-24h cap, or shift boundaries
+  ([[shift]]).
+- An operator with host access changing the system time deliberately.
+
+## What protects it
+
+- **Monotonic chain order is independent of wall-clock.** The [[append-only-event-chain]] `index`
+  is strictly increasing regardless of timestamps, so **reordering** is caught even if timestamps
+  are forged. But the *durations* used for pricing still rely on the wall clock — so:
+- **Detect clock anomalies and record them as events.** A timestamp that goes **backwards** between
+  consecutive chain events, or jumps implausibly, is an `anomaly` (the type already exists) — signed
+  and surfaced to [[reconciliation]], not silently accepted.
+- **Hardware-backed time where possible.** A battery-backed RTC on the appliance; the
+  [[atecc608]]/secure element and [[disk-os-hardening]] reduce casual tampering. An operator
+  changing time should require privilege the booth login doesn't have.
+- **Opportunistic trusted sync** when a [[reconciliation]] channel is briefly online (the same
+  USB/hotspot path) — set/check the clock against an external authority, log any correction as an
+  event.
+
+## Stance
+
+Like the rest of the system: **prevention (hardened host, privileged-only time change) first,
+detection (anomaly on clock regression, reconciliation) as the backstop.** The clock can't be made
+unforgeable on an offline box, but a forged clock can be made **visible**.
+
+## Open
+
+- RTC / time source on the chosen appliance ([[bom]]).
+- Tolerance thresholds for "implausible" jumps before flagging.
+- Whether to hard-refuse an event on a backwards clock vs. record-and-flag (record-and-flag matches
+  the append-only ethos — never drop).

wiki/concepts/device-events.md

@@ -0,0 +1,45 @@
+---
+type: concept
+tags: [parking, devices, monitoring, telemetry]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Device Events (telemetry)
+
+The **unsigned** operational record of what the hardware did and reported — distinct from the
+signed business [[append-only-event-chain|ledger]] (see [[event-streams-split]]). For monitoring,
+diagnostics, and live booth status — **not** anti-fraud.
+
+## What lands here
+
+- **Relays/barriers:** relay fired/released, pulseOpen issued (the *device-side* echo; the
+  authoritative `barrier_open_command` is a signed ledger event).
+- **Printers:** paper-out / near-end / cover-open / cutter / offline (already polled —
+  [[printer-status-monitoring]]).
+- **Cameras:** reachable/offline, snapshot success/failure ([[lpr-camera]]).
+- **Readers / inputs:** a raw read, raw input edges (Dingtian button `input N on/off` —
+  [[device-input-flow]]).
+
+## Properties
+
+- **Unsigned, not chained** — no `prevHash`/`signature`. It's telemetry, so it carries none of the
+  ledger's integrity machinery.
+- **Disposable** — high-volume and churny; **may rotate/prune** on a retention policy (the ledger
+  never does).
+- **Device-keyed** — references the `lane_devices` instance; `lane` resolved via the same `LaneMap`
+  as before. Stores raw device provenance.
+
+## The boundary that matters
+
+A device event is *evidence the host saw something happen*; it does **not** by itself authorize or
+record a business fact. A button press here becomes a **signed `vehicle_entry`** in the ledger only
+after the entry flow runs (ticket + barrier command). This keeps device chatter on the device side
+of the [[device-adapter-pattern|adapter boundary]] and the signed ledger focused on money/access.
+
+## Open
+
+- Retention/rotation policy (size- or age-based).
+- Whether any witness-grade device fact (e.g. a loop-sensor `barrier_open_observed`) should *also*
+  write a signed ledger entry for [[reconciliation]] — see [[append-only-event-chain]].

wiki/concepts/parking-session.md

@@ -0,0 +1,103 @@
+---
+type: concept
+tags: [parking, domain, business, anti-fraud]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Parking Session
+
+The core business-domain entity: one vehicle's stay, from entry to exit, plus the money owed and
+paid for it. Everything on the business side — [[tariff|tariffs]], payment, [[reconciliation]],
+revenue reporting — hangs off the session. This page defines what a session **is** and, just as
+importantly, what it is **not**.
+
+> Scope decision (2026-06-15): build the **transient** (casual, pay-for-duration) session first;
+> layer **permit holders** on top as a second identity source that short-circuits payment. Mixed
+> site, transient-first — see [[entry-exit-readers]] ("two populations, one shared relay") and
+> [[session-model]].
+
+## A session is a PROJECTION over the signed event log — not a mutable table
+
+This is the single most important rule, and it falls straight out of the [[threat-model]] (the
+adversary is the insider who can edit the database) and the [[append-only-event-chain]]:
+
+- The **events** table is the ledger and the **only** source of truth. `vehicle_entry`,
+  `vehicle_exit`, `payment`, `void` are all **appended + signed**, never updated or deleted.
+- A **session** is a **read-model folded from those events** — open when an entry has no matching
+  exit, paid when a `payment` event references it, closed when an exit lands. It MAY be cached in
+  a table for query speed (dashboards, "cars currently in"), but that cache is **always rebuildable
+  from the chain and never authoritative**. Same pattern as the `LaneMap`
+  ([[append-only-event-chain]]), scaled to the business domain.
+- **Why this matters:** a mutable `sessions` row that stored "amount owed / paid" would reopen
+  exactly the fraud hole the whole system exists to close (operator marks a session paid, pockets
+  the cash). With sessions as a projection, "paid" is a **signed `payment` event** an operator
+  can't forge or silently delete — a deletion breaks the chain visibly. See [[session-model]] for
+  the rejected mutable-table alternative.
+
+## Identity — how an entry is tied to its exit
+
+A session needs a key that survives from entry to exit. Two populations, two keys
+([[entry-exit-readers]]):
+
+- **Transient:** a **ticket id** (printed, ideally on pre-numbered stock — see [[reconciliation]])
+  or a **plate** read by [[lpr-camera|LPR]]. This id is carried in the event's `identity` field.
+- **Permit holder:** a **credential** (card / plate / QR) matched to a [[permit]] record. A valid
+  permit means the session owes nothing — the PAY step is skipped (see below).
+
+## Lifecycle (pay-on-foot / pay station model)
+
+Payment is **decoupled from exit** (decision 2026-06-15, matching the [[autonomous-direction|
+unmanned]] roadmap): the customer pays at a central station before walking back to the car; the
+exit lane only *validates* that the session is settled.
+
+```
+ENTRY (lane)      vehicle_entry event              → session OPEN
+                  (ticket printed / plate read; barrier opens)
+PAY  (pay station) payment event {sessionRef, fee, paidAt}
+                                                    → session PAID  (grace window starts)
+EXIT (lane)       validate: PAID && now ≤ paidAt + graceMinutes ?
+                    yes → vehicle_exit event        → session CLOSED → pulseOpen
+                    no  → reject → re-pay overstay top-up at station, then exit
+```
+
+States, as derived from events:
+
+| State | Condition (over the event chain) |
+| --- | --- |
+| **OPEN** | a `vehicle_entry` with no later matching `vehicle_exit` |
+| **PAID** | OPEN + a `payment` event covering the fee due, within its grace window |
+| **CLOSED** | a matching `vehicle_exit` event exists |
+| **VOIDED** | a `void` event references the session (lost ticket written off, error correction) |
+
+Permit sessions skip PAID: a valid [[permit]] at exit is itself the authorization to close.
+
+## Edge cases the model must name (not yet designed in full)
+
+- **Overstay after payment** — exited the grace window; needs a top-up payment. The one genuinely
+  stateful rule; handled as a second `payment` event, fee = f(time since paid).
+- **Lost ticket** — no entry id to match. A default flat "lost ticket" fee (see [[tariff]]), **or
+  an amount the admin sets at the moment** (operator judgement — e.g. they can establish entry time
+  from [[opencv-anpr-service|plate]] capture or CCTV and charge accordingly, or apply a fixed
+  penalty). Recorded as a `payment` (with the chosen amount + a reason) + a `void`/annotation so it
+  reconciles; the admin-set amount is captured in the signed event, attributed.
+- **Manual override** — an operator/admin opens the barrier for a stuck or disputed car, or writes
+  off a session, as a deliberate act. Each is a **signed, reason-coded event**
+  (`barrier_open_command` / a void with reason) — so an override is *authorized and logged*, while
+  an open with **no** such signed event remains the fraud signal ([[append-only-event-chain]]). The
+  override is the legitimate counterpart to the out-of-band-open anomaly.
+- **Forced / fail-open exit** — barrier failed open ([[fail-state-safety]]): the vehicle leaves with
+  **no `vehicle_exit`**. This is an open session that never closes — a **reconciliation anomaly by
+  design** ([[append-only-event-chain]]'s "physical open with no signed command"), not something to
+  paper over. (A *manual* override above is the signed, non-anomalous version.)
+- **Re-entry / never-exited** — stale open sessions (drove out tailgating, sensor missed). Surface
+  as anomalies; never auto-close silently.
+
+## What this unblocks (build order)
+
+The device layer left the entry flow dangling — `input_received` events land in the log and stop
+([[device-input-flow]] "the entry flow itself is the next build"). The session domain is that next
+step: consume `input_received` / a reader event → mint a signed `vehicle_entry` → print + open.
+Then the pay-station and exit-validation flows. Schema + code follow this page and [[tariff]];
+the decision is recorded in [[session-model]].

wiki/concepts/reporting-analytics.md

@@ -0,0 +1,48 @@
+---
+type: concept
+tags: [parking, domain, business, reporting]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Reporting & Analytics
+
+Turning the signed event log into the numbers an owner runs the business on. All reports are
+**projections over the [[append-only-event-chain]]** — the chain is the single source, reports are
+derived and rebuildable, never a separate ledger.
+
+## Reports (driven by the events already designed)
+
+- **Revenue** — by day/week/shift, by tender (cash vs. card), gross vs. discounts vs. net. Source:
+  `payment` events + [[validation-discounts|discount]] events + `shift_z_report` ([[shift]]).
+- **Occupancy** — current ([[capacity-occupancy]]) and historical curve; peak times; turnover.
+- **Stay analytics** — average/median duration, distribution; transient vs. [[permit]] split.
+- **Permit usage** — active permits, utilisation, concurrency vs. `maxConcurrent`.
+- **Anomalies** — out-of-band opens, never-exited sessions, occupancy drift, over-validation —
+  the `anomaly` events + reconciliation findings ([[reconciliation]]).
+
+## Plate / entry search (admin lookup) — user-requested 2026-06-15
+
+The admin can **search for an entry/session by licence plate** — *if the plate was captured* (by
+the [[opencv-anpr-service|vision service]] or an LPR read; a pure-ticket transient has no plate).
+Returns the matching session(s): entry/exit times, fee, payment, snapshot image. Useful for
+disputes ("I was charged for a car that left earlier"), lost-ticket lookup, and incident review.
+
+- Search keys: plate (when captured), ticket id, session id, time range.
+- Read-only over the chain; surfaces the linked snapshot ([[lpr-camera]] `imageRef`) as evidence.
+- Honest limit: **no plate → no plate-search hit.** The UI must say "not captured", not "no such
+  car", so the absence isn't mistaken for a missing record.
+
+## Properties
+
+- **Offline** ([[offline-first]]): all computed locally from the local DB; no cloud BI dependency.
+- **Reproducible**: a report run twice over the same chain gives the same answer; figures trace to
+  signed events.
+- **Export** for [[reconciliation]] / accounting (CSV/PDF) — the periodic external-authority path
+  ([[open-questions]] #4).
+
+## Open
+
+- Which reports matter at launch vs. later; the export format/cadence.
+- Dashboard (live) vs. on-demand reports.

wiki/concepts/shift.md

@@ -0,0 +1,77 @@
+---
+type: concept
+tags: [parking, domain, business, shifts, anti-fraud]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Shift (manned mode) & the Z-Report
+
+A **shift** is one operator's accountability period at a manned booth: from the moment they take
+over to the moment they hand over, however long that is. At the end, the system signs and **prints
+a Z-report** — the cash and POS totals taken during the shift. (Decisions 2026-06-15.)
+
+## Shifts exist ONLY in manned mode
+
+A shift is fundamentally a **human accountability boundary** — "this person was responsible for the
+takings from here to here." In the [[autonomous-direction|fully-automated / unmanned]] system there
+is **no operator and no shift**; what replaces it is the pay station's **cash-collection cycle**
+(who emptied the vault, when, how much vs. what the signed log expected) plus ongoing
+[[reconciliation]] — a separate concept, not a shift. So shifts are scoped to manned operation;
+don't force one model across both.
+
+## A shift is NOT time-based
+
+It is delimited by **explicit operator action**, never by a clock:
+
+- Booth reality: relief comes late, doesn't show, or one operator is **forced to work two shifts in
+  a row**. A fixed 8h boundary (or an 8h token expiry) would be wrong — it could strand an active
+  operator. So the [[local-jwt-auth|login token has no time expiry]] (valid until logout).
+- **Start Shift / End Shift are explicit, and independent of login.** One login can span many
+  shifts; a back-to-back double is simply *End Shift → Start Shift again*, no re-login. The
+  operator (the same person or the next) marks the boundary.
+
+```
+login ——————————————————————————————————————————————→ (until logout)
+   [Start shift] … takings … [End shift→sign+print Z] [Start shift] … [End shift] …
+```
+
+## What End Shift does
+
+1. Determine the shift's payment set: the signed `payment` events ([[parking-session]],
+   [[append-only-event-chain]]) between this shift's start mark and now.
+2. Sum by **tender**: `cashTotal`, and `cardTotal` from the POS/terminal **if a POS is configured**
+   (the card line is omitted when there's no terminal).
+3. Append a signed **`shift_z_report`** event (type already in `packages/shared`): `{ operator,
+   startedAt, endedAt, cashTotal, cardTotal?, paymentCount, eventRange, prevZHash }` — chained to
+   the prior Z so a missing/out-of-order Z-report is itself visible.
+4. **Print the Z-report** (cash total, POS total if any, counts, shift window, operator) on the
+   booth printer.
+
+That's the whole human-side requirement: **print the cash and the POS (if any).** No blind count,
+no variance gate, no manager override.
+
+## Where the fraud control actually lives
+
+Deliberately **not** in a shift-close ceremony. Because every payment is a **signed event in the
+append-only chain**, the printed cash figure *is* the system's tamper-evident truth. A manager
+reconciles the signed Z-report against the actual drawer and the bank/POS batch **later** — that's
+[[reconciliation]], the real control (deferred). The tradeoff vs. a heavier control is purely
+*when* a skim is caught (after the fact, by a human), not *whether*.
+
+> **Optional enhancement (not building now): blind cash count.** Have the operator enter the
+> counted cash *before* the system reveals the expected figure, and record the variance into the
+> `shift_z_report`. Blindness removes the operator's ability to back-fill their declaration to match
+> expectation, catching a skim **at close** rather than later. Explicitly out of scope per
+> 2026-06-15; documented as a clean add-on if ever wanted.
+
+## Open
+
+- **Shift ↔ session boundary:** a vehicle may enter under one shift and pay under another — the
+  Z-report sums by **payment time** (when cash/card was taken), which is the operator who handled
+  the money. Confirm that's the intended accountability (vs. by entry).
+- **Mid-shift report / X-report** (read-only "so far" total without closing) — add if booths want
+  it; the sum is the same projection.
+- **Multiple lanes/booths** — whether a shift is per-operator, per-booth, or per-site
+  (relates to [[open-questions]] #1 lane topology).

wiki/concepts/tariff.md

@@ -0,0 +1,155 @@
+---
+type: concept
+tags: [parking, domain, business, pricing]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Tariff (Fee Model)
+
+How a [[parking-session]]'s fee is computed from its duration. A tariff is **admin-composed data,
+not code** — the park owner builds and constantly edits the rate card at runtime (like a
+[[permit]]), in a selectable currency, with **no numbers hard-coded anywhere** and no code change to
+reprice. The computation is **pure and offline** ([[offline-first]]: no network, no clock authority
+beyond the host).
+
+> Decisions (2026-06-15): (1) tariffs are **effective-dated, immutable versions** — editing
+> publishes a new version, never mutates an old one; (2) **one active tariff per site** (versioned
+> over time), modelled with an id/scope so multiple rate cards can be added later without migration;
+> (3) **currency is selectable** (ISO 4217) and the money model is **FX-ready but FX is deferred**.
+
+## Design principles
+
+- **Pure function of (entry time, charge time, tariff).** `fee = f(enteredAt, asOf, tariff)`. No
+  side effects, deterministic, unit-testable. The pay station calls it with `asOf = now`; the exit
+  lane re-checks against the recorded payment.
+- **Data-driven.** The tariff lives as a config record (its own table or seeded config), versioned,
+  so a historical session always reprices against the tariff in force when it was incurred. Never
+  hard-code rates (this is an [[open-questions|open-question]]-adjacent procurement input — sites
+  differ).
+- **Integer minor units.** Money is integer cents (or the site currency's minor unit) — never
+  floats. Avoids rounding drift across a revenue ledger.
+- **The fee, once paid, is a signed `payment` event** ([[parking-session]]) — the computation is
+  reproducible, but the *charged* amount is fixed in the chain.
+
+## The composable structure — stepped blocks + daily cap
+
+The admin composes a **rate card** the fee function interprets. The general model is an **ordered
+list of duration blocks** (flat rate is just one block) plus a daily cap — chosen because it
+expresses every common operator shape (first-hour pricing, tapering, caps) with no special cases in
+code. All amounts are **integer minor units** in the tariff's currency.
+
+```jsonc
+{
+  "currency": "EUR",            // ISO 4217; selectable per tariff version
+  "gracePeriodEntryMin": 15,    // free if exited within this (drop-off/turnaround)
+  "incrementMin": 60,           // billing granularity; partial increments round UP
+  "blocks": [                   // consumed in order as duration accrues
+    { "uptoMin": 60,   "priceMinorPerIncrement": 200 },   // first hour
+    { "uptoMin": 180,  "priceMinorPerIncrement": 150 },   // 60→180 min
+    { "uptoMin": null, "priceMinorPerIncrement": 100 }    // null = open-ended, thereafter
+  ],
+  "dailyCapMinor": 1200,        // cap per rolling 24h (null = no cap)
+  "lostTicketMinor": 2000,      // flat charge when there's no entry id
+  "gracePeriodExitMin": 15,     // pay-on-foot walk-back window
+  "overstay": "reprice"         // top-up = recompute(entry→now) − alreadyPaid (decided)
+}
+```
+
+> **The numbers above are illustrative, not defaults to ship.** "No one knows the pricing and it
+> changes constantly" — so the admin authors all of it; the system ships with **no rate card** and
+> the owner must compose + publish one before the lot can charge (until then: free, or gated —
+> operator policy, see Open).
+
+**Lost ticket** is not just the flat `lostTicketMinor`: the admin may **override with an arbitrary
+amount** at the moment (operator judgement — establish entry time from [[opencv-anpr-service|plate]]
+capture/CCTV and charge real duration, or apply a set penalty). The configured flat fee is the
+default; the chosen amount is recorded in the signed `payment` event ([[parking-session]]).
+
+## The fee algorithm (pure, integer, offline)
+
+```
+fee(enteredAt, asOf, tariff):
+  minutes = roundUp(asOf − enteredAt, incrementMin)
+  if minutes ≤ gracePeriodEntryMin: return 0
+  total = 0
+  for each rolling 24h segment of the stay:
+    segMinutes = minutes within this segment
+    segFee = walk `blocks` in order, charging priceMinorPerIncrement for each
+             incrementMin that falls in each block's [prevUpto, uptoMin) range
+    if dailyCapMinor: segFee = min(segFee, dailyCapMinor)
+    total += segFee
+  return total
+```
+
+Deterministic, side-effect-free, unit-testable; the daily cap is applied **per rolling 24h** (so an
+overnight stay doesn't hit the cap twice). Rounding and segment edges are part of the settled spec
+because the chain + reconciliation depend on the result being reproducible.
+
+## The pay-on-foot consequence
+
+Because payment is decoupled from exit ([[parking-session]] lifecycle), the tariff has **two
+time references**, not one:
+
+1. At the **pay station**: `fee = f(enteredAt, now, tariff)` — charge for time parked so far.
+2. At the **exit lane**: the session is valid to leave iff `now ≤ paidAt + gracePeriodExit`.
+   Past that, an **overstay top-up** = `f(paidAt, now, tariff.overstayRate)` is due before exit.
+
+`gracePeriodExit` is therefore a real revenue/UX parameter, not a nicety: too short traps people
+who paid; too long gives free parking between pay and exit.
+
+## Permit holders
+
+A valid [[permit]] bypasses tariff computation entirely for the covered period (subscription
+already paid out-of-band). A permit that has lapsed mid-stay falls back to the transient tariff for
+the uncovered time — an edge case to design with [[permit]].
+
+## Versioning — edits publish immutable, effective-dated versions
+
+Prices change constantly, **and** a historical [[parking-session]] must reprice against the rate
+that was in force when it was incurred — never today's. So a tariff is **never edited in place**:
+
+- Each save **publishes a new version** with an `effectiveFrom` timestamp; prior versions are
+  **immutable**. Picking the version for a session = "the latest version with `effectiveFrom ≤
+  session entry time`".
+- The session's **`payment` event records the `tariffVersionId`** it was priced under
+  ([[parking-session]], [[append-only-event-chain]]). The charged amount is then both reproducible
+  *and* fixed in the signed chain — an admin can't retroactively rewrite prices to alter what a past
+  session "should have" paid without it being visible.
+- An **in-progress** session that crosses a version boundary uses the version in force at **entry**
+  (consistent, predictable) — confirm vs. pro-rating if an operator ever wants the latter.
+
+## Data model (first cut — with [[session-model]])
+
+| Table / field | Notes |
+| --- | --- |
+| `tariffs` | a logical rate card: `id`, `scope` (site/lane/zone — only "site" used now), `name`. |
+| `tariff_versions` | `id`, `tariffId`, `effectiveFrom`, `currency`, `structure` (the JSON above), `createdBy`, `createdAt`. **Immutable.** |
+| (active) | "one active tariff per site" = one `tariffs` row; multiple `tariff_versions` over time. The `scope`/`id` exist so multiple rate cards can be added later **without migration**. |
+
+Unlike the event log, tariff data is **mutable master data** in the sense that new versions are
+*added*; but each version row, once published, is never changed — close to append-only, and the
+*use* of it is fixed in the signed `payment` event.
+
+## Currency & FX — selectable now, FX deferred
+
+- Each `tariff_version` names its **`currency`** (ISO 4217), admin-selectable. Amounts everywhere
+  are `{ minorUnits, currency }` — never a bare number, never a float.
+- A `payment` event stores its **`currency`** and a reserved **`fxRate` (null for now)** + optional
+  `baseCurrency`. So when an exchange-rate system is added later, historical payments stay
+  reproducible (you know the currency charged and, once FX exists, the rate applied) — **no
+  migration** of stored amounts.
+- **FX engine is NOT built now.** When it is, it needs an *offline* rate source (rates can't depend
+  on the network — [[offline-first]]), a base currency, and a rounding policy. Deferred to
+  [[open-questions]].
+
+## Open
+
+- The **actual rate cards** are owner-authored at runtime — nothing to confirm at build time; the
+  composer UI + validation (sane blocks, non-negative, ordered `uptoMin`) is the work.
+- **Time-of-day / weekday tiers** — not in the block model yet; add as a tier wrapper if a site
+  needs day/night/weekend cards (deferred until asked).
+- **Blank-tariff policy** — free vs. gated until a rate card is published (operator policy).
+- **In-progress version-boundary** — entry-version (decided) vs. pro-rate (revisit if needed).
+- **FX** — exchange-rate system, offline rate source, base currency ([[open-questions]]).

wiki/concepts/ticket-encoding.md

@@ -0,0 +1,54 @@
+---
+type: concept
+tags: [parking, domain, business, devices, entry-flow]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Ticket Encoding & Scanning
+
+How a transient [[parking-session]]'s **ticket id** is printed, carried by the customer, and read
+back at the pay station and exit. This is the **physical backbone of the transient flow** — the
+thing that links entry → pay → exit when there's no plate.
+
+## The ticket id is the session key
+
+At entry the system mints a `vehicle_entry` event with a **ticket id** (`identity`) and prints a
+ticket the customer keeps. That same id is read back later to find the session. Properties the id
+must have:
+
+- **Opaque + unguessable** — a random id (not a sequential count an attacker could iterate to claim
+  someone else's cheaper session). Sequential **physical** stock numbering is a separate
+  reconciliation aid ([[reconciliation]] pre-numbered stock), not the scan key.
+- **Single logical session** — scanning it at the pay station finds the open session; after payment
+  it's the proof-of-paid the exit checks.
+
+## Encoding: QR (preferred) — printed by the booth dispenser
+
+- The [[rongta-printer]] prints the ticket id as a **2D barcode (QR)** plus human-readable text and
+  entry time. QR over 1D barcode: denser, tolerant of crumpling/partial reads, easy for a cheap
+  camera/imager to read.
+- **Scan points** (both host-side reads — [[entry-exit-readers]]):
+  - **Pay station** — customer scans the ticket → host finds the session → shows fee → takes
+    payment ([[tariff]], pay-on-foot) → appends `payment`.
+  - **Exit lane** — customer scans the (now paid) ticket → host validates paid + within
+    `gracePeriodExit` → `vehicle_exit` → `pulseOpen`.
+- The **scanner is a device behind an adapter** ([[device-adapter-pattern]]): a new `ReaderDevice`
+  kind (QR/barcode imager) — likely the same `IdentitySource = "ticket"` / `"qr"` path. Keeps the
+  app device-agnostic; hardware model is procurement ([[bom]], [[open-questions]]).
+
+## Ticketless alternative (plate as the ticket)
+
+Where the [[opencv-anpr-service|vision service]]/LPR captures the plate, the **plate can be the
+session key** instead of a printed ticket — drive in, plate read, drive to pay station and enter
+plate (or it's looked up), pay, exit by plate. No paper. The two can coexist per lane
+([[entry-exit-readers]] "both share a relay"); a printed QR ticket is the fallback when a plate
+isn't captured or is low-confidence (recognition is advisory — [[opencv-anpr-service]]).
+
+## Open
+
+- QR symbology/error-correction level + what else prints (site name, tariff summary, help number).
+- Scanner hardware (imager model; same unit at pay station and exit?).
+- Lost/damaged ticket → the lost-ticket path ([[parking-session]], [[tariff]] admin-arbitrary
+  amount).

wiki/concepts/validation-discounts.md

@@ -0,0 +1,46 @@
+---
+type: concept
+tags: [parking, domain, business, pricing, revenue]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Validation & Discounts
+
+A merchant (shop, hotel, clinic) **validates** a customer's parking so they pay less or nothing —
+a common revenue/retention feature that modifies what a [[parking-session]] owes.
+
+## Model: a discount is a signed event, applied at fee time
+
+A validation is **not** an edit to the session or a mutable "discount applied" flag — same reason
+as everything else ([[threat-model]]: an operator/merchant could otherwise fake free parking). It's
+recorded so the fee computation and the audit both see it:
+
+- A **discount/validation event** references the session: `{ sessionRef, kind, value, issuedBy,
+  ts }` — e.g. *2 hours free*, *€5 off*, *flat €1*, *100% off*. Appended + signed
+  ([[append-only-event-chain]]).
+- The [[tariff]] fee function applies eligible validations when computing what's due at the pay
+  station: `due = max(0, tariff_fee − discounts)` (or time-based: subtract validated minutes before
+  pricing). Pure + reproducible, like the base fee.
+- The `payment` event then records gross fee, discount total, and net paid — so revenue reporting
+  ([[reporting-analytics]]) can show **discount leakage** (how much was given away, by whom).
+
+## How a validation is presented
+
+- **Merchant terminal / portal** stamps the customer's ticket id (or plate) — issues the validation
+  event for that session.
+- Or a **validation code** the customer enters at the pay station.
+- Either way it ties to the session by **ticket id or plate** ([[parking-session]] identity).
+
+## Anti-abuse
+
+Because each validation is signed and attributed (`issuedBy`), over-validation by a colluding
+merchant is **visible to [[reconciliation]]** (a merchant validating far more than their footfall is
+an anomaly), rather than invisible free parking.
+
+## Open
+
+- Validation types the site needs (free hours / fixed amount / percentage / flat rate).
+- Whether merchants self-serve (portal/terminal) or the operator applies it.
+- Caps (max discount, max per merchant/day).

wiki/decisions/event-streams-split.md

@@ -0,0 +1,57 @@
+---
+type: decision
+tags: [parking, decisions, integrity, devices, schema]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Decision: Split the signed business ledger from device telemetry
+
+Taken 2026-06-15, at the start of the business-layer schema work.
+
+## The problem
+
+The existing `events` table (signed, hash-chained — [[append-only-event-chain]]) had grown to carry
+**two unrelated concerns**: the financial/accountability ledger *and* raw device telemetry (button
+pushes recorded as `input_received`). They have opposite requirements — the ledger must be small,
+signed, and reconciled; telemetry is high-volume, churny, and disposable.
+
+## Decision — two tables
+
+- **`ledger_events`** — the signed, hash-chained, [[atecc608]]-signed **business ledger** (rename of
+  `events`). Holds only business/accountability facts: `vehicle_entry`, `vehicle_exit`, `payment`,
+  `void`, `shift_z_report`, and the witness-grade `barrier_open_command` / `barrier_open_observed` /
+  `anomaly`. [[reconciliation]] runs against this; sessions/[[tariff]]/occupancy are projections of
+  it.
+- **`device_events`** — **unsigned** operational telemetry (see [[device-events]]): relay fired,
+  printer paper-out, camera offline, reader read, raw input edges. May rotate/prune. Never signed,
+  never reconciled.
+
+A raw button press is **telemetry** → `device_events`. The entry flow then mints a **signed
+`vehicle_entry`** in the ledger once a ticket prints + the barrier is commanded. So
+`input_received`-as-a-signed-event is **dropped** (it was transitional).
+
+## Why
+
+- Keeps the **signed ledger small and high-value** — fewer rows to sign, hash, verify, reconcile,
+  and export; signal isn't drowned in device noise.
+- Right **durability semantics per stream**: the ledger is precious + append-only forever; telemetry
+  can age out.
+- Clean separation matches the [[device-adapter-pattern]] philosophy — device chatter stays on the
+  device side of the boundary.
+
+## Consequences / migration (no production data yet)
+
+- No `.sqlite` with real chain data exists, so renaming + restructuring is safe now (no signatures
+  to invalidate). This is the moment to do it.
+- Code: rename `events` → `ledger_events`; `EventLog`/`canonicalize`/`verifyChain` and the
+  `/api/events` routes follow the rename; add an unsigned `device_events` writer; move the Dingtian
+  input-push handler to emit `device_events` (+ the entry flow signs `vehicle_entry`).
+- `ParkingEventType` in `packages/shared` splits into ledger types vs. a device-event type set.
+
+## Open
+
+- `device_events` retention/rotation policy.
+- Which device facts (if any) are witness-grade enough to *also* warrant a signed ledger entry
+  (e.g. `barrier_open_observed` from a loop sensor) — see [[append-only-event-chain]] witness gap.

wiki/decisions/open-questions.md

@@ -24,7 +24,12 @@ status: open
    manager visit) to reconcile the signed log against an external authority — the real anti-fraud
    control. See [[reconciliation]].
 5. **Durability / backup.** Backup strategy for the [[sqlite]] database + recovery plan; "sync
-   later" currently leaves a disk failure as **total revenue-history loss**.
+   later" currently leaves a disk failure as **total revenue-history loss**. _(Confirmed in-scope
+   to design, 2026-06-15.)_ Because the DB is the signed [[append-only-event-chain]], a backup must
+   preserve the chain intact (a restored copy must still `verifyChain`); options include SQLite
+   WAL/online-backup snapshots to a second disk/USB + the periodic external export that doubles as
+   the [[reconciliation]] channel (#4). Encryption at rest already applies ([[disk-os-hardening]]).
+   Design TBD.
 6. **Secure-element integration.** Confirm [[atecc608]] wiring/usage on the host (event
    signing). The [[esp32-custom-controller]] command-authentication use is **deferred — not
    being implemented for now** (access control is the [[dingtian-relay]] behind
@@ -39,3 +44,15 @@ status: open
    compromising a verifying host yields nothing that can forge a token. Decide before
    multi-host / multi-lane deployment (see #1 lane topology), since that's when shared-secret
    distribution becomes the liability.
+8. **Exchange-rate (FX) system.** _(Raised by the [[tariff]] design, 2026-06-15.)_ Currency is
+   selectable per tariff version and the money model is FX-ready (`payment` stores currency + a
+   reserved `fxRate`), but **no conversion is built**. If multi-currency pricing/charging is ever
+   needed, it requires an **offline** rate source (rates can't depend on the network —
+   [[offline-first]]), a base currency, and a rounding policy. Deferred; nothing blocks adding it
+   later without migrating stored amounts.
+9. **Pay-station money corners — receipts & refunds/change.** _(Raised by the scope sweep,
+   2026-06-15; deferred until pay-station hardware is chosen.)_ Not yet designed: **receipts / VAT
+   invoices** (fiscal receipt with tax number + sequential numbering may be legally required — could
+   change what the `payment` event must store) and **refunds / overpayment / change** (cash change,
+   "exact change only", a refund as a signed reversal event). Both depend on the unmanned-vs-manned
+   payment subsystem (#3) and the note/coin/card acceptor hardware. Revisit at procurement.

wiki/decisions/session-model.md

@@ -0,0 +1,55 @@
+---
+type: decision
+tags: [parking, decisions, domain, business]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Decision: Parking Session Model
+
+The starting decision for the **business layer**, taken 2026-06-15 as the project pivots from the
+(now hardware-verified) device/integrity layer to the parking *operation*.
+
+## Decisions
+
+1. **A session is a projection over the signed event log, not a mutable table.** The
+   [[append-only-event-chain]] `events` table stays the only source of truth; a
+   [[parking-session]] is folded from `vehicle_entry` / `vehicle_exit` / `payment` / `void`
+   events. A cache table is allowed for query speed but is always rebuildable and never
+   authoritative.
+2. **Transient-first, mixed site.** Model the casual pay-for-duration session + [[tariff]] first;
+   layer [[permit]] holders on top as a second identity source that short-circuits payment
+   ([[entry-exit-readers]]).
+3. **Pay-on-foot / pay station.** Payment is **decoupled from exit**: the customer pays at a
+   central station; the exit lane only validates the session is paid and within the walk-back
+   grace window before opening ([[parking-session]] lifecycle). Matches the
+   [[autonomous-direction|unmanned]] roadmap and sharpens [[open-questions]] #3 toward an unmanned
+   pay station (PCI scope still kept out of the app via a certified terminal).
+4. **New signed event types:** `vehicle_entry`, `vehicle_exit`, `payment`, `void` — extend the
+   existing `input_received`. Recorded in [[append-only-event-chain]].
+
+## Why (rejected alternative)
+
+A **mutable `sessions` table** carrying `amountOwed` / `paidStatus` as the source of truth was
+rejected: it reopens the exact fraud vector the system exists to close ([[threat-model]] — the
+insider edits the row, marks it paid, pockets the cash). Making "paid" a **signed `payment`
+event** means it can't be forged and can't be silently deleted (a deletion breaks the chain). The
+projection approach costs a fold/cache but keeps the anti-fraud guarantee intact end-to-end.
+
+## What this unblocks
+
+Closes the dangling thread from [[device-input-flow]] ("the entry flow itself is the next
+build"): `input_received` → signed `vehicle_entry` → ticket print → `pulseOpen`, then the
+pay-station and exit-validation flows. Schema (`packages/db`) + shared types follow the
+[[parking-session]] + [[tariff]] design pages.
+
+## Open / next
+
+- Rate card, currency, grace windows, caps — operator/procurement input ([[tariff]]).
+- Tariff versioning (effective-dated) for historical repricing.
+- [[permit]] data model + lapsed-mid-stay handling.
+- Wire payment capture to a concrete pay-station terminal ([[open-questions]] #3) — kept abstract
+  (payment = an independent signed event referencing a session) until procurement settles.
+- Reconciliation of sessions/payments against an external authority remains [[open-questions]] #4
+  + the unbuilt witness/reconciliation gap in [[append-only-event-chain]].

wiki/decisions/standing-decisions.md

@@ -14,6 +14,10 @@ The decisions treated as settled in the design notes. (See [[parking-system-arch
 - **Stack:** [[turborepo]] · [[fastify]] (Node) · [[react-vite-spa]] · [[sqlite]] +
   [[drizzle-orm]] · [[local-jwt-auth]]. All MIT/Apache/BSD — **no vendor lock, no rug-pull
   risk** (see [[payload-cms]]). Full table in [[technology-stack]].
+  - **Scoped exception (2026-06-15):** the [[opencv-anpr-service]] — a **separate local process**,
+    not linked into the app — **may use AGPL** components (plate/vehicle models). The exception is
+    bounded to that process; the Node/React app stays strictly MIT/Apache/BSD. See
+    [[vision-service]].
 - **Platform:** a **dedicated, hardened Linux appliance** (LUKS + GRUB password + Secure Boot),
   **not Windows/WSL** — see [[disk-os-hardening]].
 - **Integrity:** append-only, hash-chained, [[atecc608]]-signed event log

wiki/decisions/vision-service.md

@@ -0,0 +1,61 @@
+---
+type: decision
+tags: [parking, decisions, vision, anpr, anti-fraud]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Decision: Host-side Vision Service (ANPR + vehicle verification)
+
+Taken 2026-06-15, as part of the business-layer build ([[session-model]]).
+
+## Decisions
+
+1. **Build a host-side vision service** ([[opencv-anpr-service]]) that does ANPR (plate → identity)
+   **and** vehicle-attribute verification (anti-spoofing witness) on snapshots from ordinary
+   Hikvision/Dahua cameras.
+2. **It replaces the dedicated edge-AI [[lpr-camera]]** as the recognition path: ordinary IP cam →
+   snapshot (`Snapshot.bytes`, already pulled by the camera driver) → vision service → plate +
+   vehicle. Removes the special LPR camera from the [[bom]] as a requirement (still allowed as an
+   option).
+3. **Deployment: a separate local Python/OpenCV microservice** on the appliance, called over
+   **localhost HTTP** by the Node backend. Fully offline ([[offline-first]]); its own process and
+   failure domain; the host falls back to the ticket path if it's unavailable.
+4. **Licensing exception:** AGPL components (e.g. YOLO plate/vehicle models, OpenALPR) are
+   **permitted inside this service only**, because it's a separate process not linked into the app —
+   the app stays strictly MIT/Apache/BSD. Amends [[standing-decisions]].
+5. **Recognition is advisory, evidence is authoritative.** A read never single-handedly authorizes
+   a paid/access barrier open; it flags for [[reconciliation]] and attaches (with the source image)
+   to the signed [[append-only-event-chain]] entry. Low confidence → fallback, never strand a car
+   ([[fail-state-safety]]).
+
+## Why
+
+- **Replace vs. edge-AI camera:** host-side recognition on cheap IP cams shifts cost from per-lane
+  smart cameras to one compute box + our software; gives us the raw image for the second job below.
+- **Vehicle verification is the real prize (user-driven, 2026-06-15):** plate-only ANPR can't catch
+  a **printed/spoofed plate on a different car**. Extracting vehicle attributes/fingerprint lets the
+  system reconcile *the car*, not just the number — directly filling the independent-witness gap the
+  [[append-only-event-chain]] calls out as unbuilt.
+- **Separate-process + AGPL-scoped** keeps the app's permissive-license guarantee intact while not
+  crippling accuracy (the strict permissive-only ANPR path is markedly weaker — that tradeoff was
+  weighed and the scoped exception chosen).
+
+## Rejected / alternatives
+
+- **Strict permissive-only ANPR in-app** — license-clean but weaker accuracy and more build; the
+  separate-process AGPL exception was chosen instead.
+- **Keep the edge-AI LPR camera as primary** — viable fallback if host-side accuracy disappoints;
+  not chosen now, kept on the table in [[opencv-anpr-service]].
+- **Embed OpenCV in Node** (opencv4nodejs/WASM) — rejected: native-build pain, weaker model
+  ecosystem, no process isolation, shares the app's failure + license surface.
+
+## Open / next
+
+- Recognizer + vehicle-model selection and accuracy targets; fingerprint method + anomaly
+  threshold ([[opencv-anpr-service]]).
+- Appliance compute footprint (CPU vs. small GPU/NPU) — [[bom]] / [[open-questions]].
+- Service API + the Node-side adapter; per-camera opt-in wiring.
+- Reconciliation logic that consumes plate+vehicle witness vs. commanded opens (still unbuilt — see
+  [[append-only-event-chain]], [[reconciliation]]).

wiki/entities/blocklist.md

@@ -0,0 +1,35 @@
+---
+type: entity
+tags: [parking, domain, business, access-control]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Blocklist (Banlist)
+
+Plates or credentials the lot **refuses** — barred vehicles (non-payers, abusers, court orders) and
+revoked/stolen cards. Checked in the entry flow.
+
+## Model
+
+- A `blocklist` table of `{ kind: 'plate' | 'card' | 'qr', value, reason, addedBy, addedAt }` —
+  admin-managed master data (mutable: add/lift a ban).
+- **Entry check:** after identifying the vehicle ([[parking-session]] identity — plate via
+  [[opencv-anpr-service|vision]]/LPR, or card/QR), if it matches an active blocklist entry, **refuse
+  entry** and append a signed event (`anomaly` / a refused-entry record) so the attempt is logged.
+- **Exit is never blocked** — a barred car already inside must still leave ([[fail-state-safety]]:
+  never trap a vehicle). A blocklist hit at exit is logged for follow-up, not used to detain.
+
+## Notes
+
+- Plate matching depends on capture quality — a blocklist-by-plate is only as good as the
+  [[opencv-anpr-service|vision]] read; treat a near-miss as a flag for a human, not an automatic
+  refusal that could strand a misread innocent car.
+- Bans are attributed (`addedBy`) and their enforcement is logged, so the control is auditable
+  ([[reconciliation]]) rather than an invisible operator lever.
+
+## Open
+
+- Plate-match tolerance (exact vs. fuzzy) and the false-positive handling.
+- Expiry / review of bans.

wiki/entities/local-jwt-auth.md

@@ -13,7 +13,14 @@ Authentication and authorization, kept **fully local** — a direct consequence
 
 - `@fastify/jwt` signs tokens with a **local secret** (symmetric HMAC). The server **refuses to
   start** without a strong `JWT_SECRET` (≥32 chars, no placeholder) — there is deliberately no
-  insecure default — and mints tokens with an **8h expiry** (bound to a shift).
+  insecure default.
+- **Session lifetime: valid until explicit logout — no time expiry** (decision 2026-06-15).
+  Booth reality breaks any fixed clock: relief arrives late, fails to show, or one operator is
+  forced to work two shifts in a row — a token that expired mid-duty would strand an active
+  operator. So the login persists until logout; a **[[shift]] is a separate, explicit boundary**,
+  not tied to token lifetime. (Superseded the earlier "8h expiry, bound to a shift" assumption.)
+  > ⚠️ Code still mints an 8h-expiry token — this page records the decided design; the server
+  > change (drop `expiresIn`, persist until logout) is pending.
 - A `users` table in [[sqlite]] holds **bcrypt** password hashes plus a **role** column. The
   first admin is seeded via `pnpm --filter @parking/server seed-admin` (no bootstrap endpoint).
 - Authorization = a simple `preHandler` role guard per route: **admin / operator / cashier /

wiki/entities/lpr-camera.md

@@ -7,12 +7,17 @@ updated: 2026-06-15
 
 # LPR Camera
 
-License-plate-recognition camera (recommended: **Milesight edge-AI LPR**). For
+License-plate-recognition camera. For **casual/transient** vehicles, the **plate acts as ticket +
-**casual/transient** vehicles, the **plate acts as ticket + an independent record**. (See
+an independent record**. (See [[parking-system-architecture]] §8, §9.)
-[[parking-system-architecture]] §8, §9.)
 
-- **Edge AI**: recognition runs **on-device**, so it keeps working with no internet — fits
+> **Superseded direction (2026-06-15):** recognition now runs **host-side** on snapshots from
-  [[offline-first]].
+> ordinary Hikvision/Dahua cameras via the [[opencv-anpr-service]], **not** on a dedicated edge-AI
+> LPR camera — see [[vision-service]]. The edge-AI camera below is kept as the original assumption /
+> a fallback option, but is no longer the planned path. The host-side service also does **vehicle
+> verification** (anti-plate-spoofing), which an edge-LPR camera does not.
+
+- **Edge AI (original assumption)**: recognition runs **on-device**, so it keeps working with no
+  internet — fits [[offline-first]].
 - It's a **host-side** identity source: only the host sees the read; the host decides and
   commands the relay open (the [[uhppote-controller]] is demoted to a commanded relay for that
   lane). See [[entry-exit-readers]].

wiki/entities/opencv-anpr-service.md

@@ -0,0 +1,85 @@
+---
+type: entity
+tags: [parking, vision, anpr, anti-fraud, service]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# OpenCV ANPR / Vision Service
+
+A **local microservice** that analyses camera snapshots: reads the licence **plate** (ANPR) and
+extracts **vehicle attributes** for verification. Built by us (decision 2026-06-15) to do
+recognition **host-side on ordinary IP-camera snapshots**, replacing the dedicated edge-AI
+[[lpr-camera]]. See decision [[vision-service]].
+
+## Two jobs
+
+1. **Identity (ANPR).** snapshot → `{ plate, confidence, bbox }`. Feeds the existing
+   `IdentitySource = "lpr"` ([[parking-session]]): the plate is a session/identity key and the way
+   a plate-bound [[permit]] is matched.
+2. **Verification (anti-fraud witness).** snapshot → vehicle attributes — at minimum
+   `{ make?, model?, colour, bodyType }`, ideally a compact **visual fingerprint** (an embedding).
+   This is the answer to **plate-spoofing**: *a fraudster prints a registered/paid plate and drives
+   in with a different car.* Plate-reading alone can't catch that; comparing the **vehicle** seen at
+   entry vs. exit (and vs. the [[permit]]'s known car) can. A plate that entered on a red hatchback
+   but exits on a black SUV is a **reconciliation anomaly** — exactly the independent-witness role
+   the [[append-only-event-chain]] flags as the unbuilt gap. See [[reconciliation]].
+
+> The two jobs are why this is worth building rather than just plate-OCR: the service is both an
+> **identity source** and an **independent witness**, the visual analogue of the whole system's
+> "two records that must reconcile" thesis.
+
+## Architecture — separate localhost process
+
+- A **Python service** (e.g. FastAPI) running **on the appliance**, called by the Node backend over
+  **localhost HTTP** (`POST /analyze` with the JPEG bytes the camera driver already pulls — see
+  [[lpr-camera]] "driver/storage boundary": `Snapshot.bytes`).
+- **Fully offline** ([[offline-first]]): all inference is local, no cloud. Model weights ship on the
+  appliance.
+- **Process isolation is deliberate** — it keeps a heavy Python/native/AGPL stack out of the
+  Node app's process and license surface (see licensing below), and gives it its own failure
+  domain. If the service is down/slow, the host falls back (transient ticket path) rather than
+  blocking the lane.
+- **Request/response (first cut):**
+  - `POST /analyze` → `{ plate: {text, confidence, bbox}|null, vehicle: {colour, bodyType, make?, model?, embedding?}, modelVersion, tookMs }`
+  - `GET /health` → readiness + model versions.
+- The Node side wraps it behind an internal interface (like a device adapter) so the recognizer can
+  be swapped without touching business logic.
+
+## Licensing — scoped AGPL exception (amends the standing rule)
+
+The app is strictly **MIT/Apache/BSD** ([[technology-stack]], [[standing-decisions]]). Accurate
+ANPR/vehicle models are mostly **AGPL** (YOLO/Ultralytics detectors, OpenALPR) or commercial.
+Decision (2026-06-15): **allow AGPL inside this service only.** It is a **separate process**, not
+linked into the app, so its obligations don't reach the Node/React codebase; the app's permissive
+guarantee is preserved. Recorded as an explicit exception in [[standing-decisions]] /
+[[vision-service]].
+
+- OpenCV core itself is **Apache-2.0** (clean either way).
+- AGPL note: if the appliance is ever offered as a network service to third parties, AGPL's
+  network-use clause could require offering the service's source — relevant only if productised
+  beyond the on-site appliance; flag at that point.
+
+## Anti-fraud / threat-model fit
+
+- **Plate spoofing** (the motivating case): vehicle-attribute / fingerprint mismatch entry↔exit or
+  vs. a [[permit]]'s registered car → anomaly. Doesn't *block* on its own (recognition is
+  probabilistic) — it **flags for [[reconciliation]]** and is captured in the signed record.
+- The recognition result and the source image both attach to the signed [[append-only-event-chain]]
+  entry, so the *evidence* is tamper-evident even though recognition itself is host-side and
+  fallible.
+- Recognition is **advisory, never the sole authority** to open a barrier where money/access is at
+  stake — confidence thresholds + fallback to ticket/manual; a low-confidence read must not strand a
+  car ([[fail-state-safety]]).
+
+## Open
+
+- **Recognizer choice** (permissive-only vs. AGPL model) and accuracy targets — see
+  [[vision-service]]; AGPL now permitted in-service.
+- **Vehicle fingerprint**: attribute classifier vs. embedding-similarity; what threshold makes a
+  mismatch an anomaly without false-positiving on lighting/angle.
+- **Compute footprint** on the appliance (CPU-only vs. a small GPU/NPU) — procurement input
+  ([[bom]], [[open-questions]]).
+- Per-camera **opt-in** ("optionally bound", user's word): which lanes/cameras route snapshots to
+  the service.

wiki/entities/permit.md

@@ -0,0 +1,119 @@
+---
+type: entity
+tags: [parking, domain, business, subscriptions, identity]
+sources: []
+updated: 2026-06-15
+status: open
+---
+
+# Permit (Subscription)
+
+A **subscription**: a known holder authorized to enter/exit without paying per-stay, for a covered
+period. The second of the "two populations" ([[entry-exit-readers]]); a valid permit
+**short-circuits the payment step** of a [[parking-session]] ([[session-model]]). Transient is
+built first; permits layer on top.
+
+## Credentials (how a permit is presented) — confirmed with operator 2026-06-15
+
+A permit is recognized by a credential read at the lane. Two kinds, mapping to the two identity
+paths:
+
+- **RF tag / chip / card.** An RFID/proximity credential. Read **host-side** (reader → host →
+  `pulseOpen`): autonomy isn't required (resolved below), and the [[dingtian-relay]] has no onboard
+  card list anyway, so there's no need to route RF into a controller. A Wiegand-out reader is still
+  fine and keeps a future autonomous path open ([[entry-exit-readers]]), but isn't required.
+- **QR code.** Read by the **optical reader** — inherently **host-side** ([[entry-exit-readers]]:
+  pure optical/network readers are invisible to a controller). Host decodes the QR → looks up the
+  permit → decides.
+
+Both feed the host as a reader event whose `source` is `wiegand` / `qr` (the `IdentitySource`
+already in the model) and whose value is the credential id.
+
+## Two optional, independent bindings — confirmed 2026-06-15
+
+A permit has **two constraints the admin may or may not apply**, orthogonally. Either, both, or
+neither — the four combinations are all valid.
+
+### 1. Car-count binding (default: 1)
+
+- **Optional.** By default a permit is bound to **1 car at a time**. The admin may raise the limit
+  (a household, a company fleet) or **unbind it entirely** (no cap on how many cars use it).
+- The limit is on **cars inside at once** (`maxConcurrent`), enforced over the
+  [[parking-session]] projection: at entry, count the permit's currently-open sessions; if
+  `< maxConcurrent` (or unbound) allow, else reject (allowance full). This is exactly why
+  sessions-as-projection matters — "how many of this permit's cars are inside right now" is a fold
+  over open entry/exit events, **not a counter someone can edit**.
+
+### 2. Plate binding (default: off)
+
+- **Optional.** By default a permit is **not** plate-bound — any car may use it (identity is the
+  card/QR). The admin may bind it to a set of specific licence plates.
+- When **bound**, an allowed plate is an **accepted identity in its own right** — a valid
+  **card/QR OR a matching plate** opens the lane (either, not a second factor):
+
+```
+entry: read card/QR → find permit → car-count ok → open
+   OR  LPR plate ∈ permit's bound plates → find permit → car-count ok → open
+```
+
+- **Accepted tradeoff:** card-OR-plate is the most convenient but does **not** prevent
+  card-sharing (a lent card still opens). Fine for a trusted permit population; the signed
+  [[append-only-event-chain]] records exactly which credential/plate entered, so abuse is visible
+  to [[reconciliation]] after the fact.
+- **Plate-spoofing defence:** a printed copy of a registered plate on a *different* car is caught
+  not here but by the [[opencv-anpr-service]]'s **vehicle-attribute verification** — the seen car
+  must reconcile with the permit's known car, not just the plate string.
+
+> The two are independent: a plate-bound permit may have no car cap; a car-capped permit may accept
+> any plate. The binding fields are simply absent/null when a constraint isn't applied.
+
+## Data model (first cut — to firm up with [[session-model]])
+
+A `permits` table (and supporting rows). Unlike the event log, reference/master data like permits
+**is** mutable (an admin grants/revokes/renews) — but every *use* of a permit still produces a
+signed `vehicle_entry`/`vehicle_exit` event in the [[append-only-event-chain]], so the audit trail
+stays append-only even though the permit record itself is editable.
+
+| Field | Notes |
+| --- | --- |
+| `id`, `holderName`/contact | the subscriber |
+| `credentials[]` | one or more: `{ kind: 'rf' \| 'qr', value }` |
+| `maxConcurrent` | car-count binding; **default 1**, raise for fleets, or `null` = unbound |
+| `plates[]` | plate binding; **default empty/false** = any car; when set, these plates are accepted identities |
+| `validFrom`, `validTo` | coverage window |
+| `status` | active / suspended / revoked |
+
+> Both bindings are nullable/empty by default — a bare permit is "1 car at a time, any plate,
+> identified by its card/QR".
+
+## Interaction with the session model
+
+- **Entry:** credential read → permit lookup → valid (active, in window, plate allowed **if
+  plate-bound**, concurrent cars `< maxConcurrent` **if car-bound**) → signed `vehicle_entry`
+  (source = `wiegand`/`qr`/`lpr`), open barrier. No ticket, no fee. (A bare permit applies neither
+  extra check — just active + in window.)
+- **Exit:** credential/plate read → matching open permit session → signed `vehicle_exit`, open. No
+  payment required.
+- **Lapsed mid-stay:** permit expires while a car is parked → the uncovered time falls back to the
+  transient [[tariff]] (edge case to design).
+- **Revoked:** a revoked permit fails the entry check → treated as transient (take a ticket) or
+  refused, per policy (OPEN).
+
+## Resolved (2026-06-15)
+
+- **Two optional bindings, independent:** car-count (`maxConcurrent`, **default 1**, raisable or
+  unbound) and plate-binding (`plates[]`, **default off** = any car). Either, both, or neither.
+- **Plate vs. credential:** when plate-bound, **card/QR OR matching plate** — either is accepted
+  identity (not a second factor); card-sharing not prevented by design, caught by
+  [[reconciliation]] after.
+- **Autonomy:** **host-in-the-loop for everything** — no onboard card list needed, so the
+  [[dingtian-relay]] stays sufficient (no new controller). Permit entry **fails closed** if the
+  host is down ([[fail-state-safety]]). One code path for transient + permit.
+
+## Open questions
+
+1. **Reader hardware** — confirm the RF reader and the QR/optical reader models (procurement;
+   relates to [[bom]] and [[open-questions]]). RF need not be Wiegand now that autonomy isn't
+   required, but a Wiegand-out reader keeps options open.
+2. **Lapsed-mid-stay & revoked** policy (fall back to transient [[tariff]] vs. refuse) — confirm
+   with operator.

wiki/index.md

@@ -7,7 +7,7 @@ updated: 2026-06-14
 # Index
 
 Content catalog for the wiki. Start at [[overview]]. Maintained on every ingest.
-Counts: 1 source · 15 entities · 12 concepts · 2 decision records.
+Counts: 1 source · 18 entities · 23 concepts · 5 decision records.
 
 ## Overview & navigation
 - [[overview]] — the top-level synthesis and entry point.
@@ -71,13 +71,31 @@ Counts: 1 source · 15 entities · 12 concepts · 2 decision records.
 - [[entry-exit-readers]] — two populations, two integration paths; both can share a relay.
 - [[uhppote-vs-esp32]] — comparison: detection vs. prevention.
 
+## Concepts — business domain
+- [[parking-session]] — the core domain entity; a projection over the signed log, never a mutable table.
+- [[tariff]] — fee model; pure, data-driven, offline; pay-on-foot adds a walk-back grace window.
+- [[shift]] — manned-only accountability period; explicit Start/End (not time-based); End → signed + printed Z-report (cash + POS).
+- [[capacity-occupancy]] — live count = open sessions; refuse entry + FULL sign when full; exit never blocked.
+- [[validation-discounts]] — merchant validates a ticket → signed discount event applied at fee time.
+- [[reporting-analytics]] — revenue/occupancy/stay reports + plate-search, all projections over the signed log.
+- [[clock-integrity]] — fees depend on the host clock; detect/flag backdating on an offline box.
+- [[ticket-encoding]] — transient ticket id as QR; printed at entry, scanned at pay station + exit; plate-as-ticket alt.
+- [[anti-passback]] — block/flag one id entering twice without an exit; fold over open sessions.
+- [[device-events]] — unsigned hardware telemetry (relay/printer/camera/reader/input); separate from the signed ledger.
+- [[permit]] — subscription; RF/QR or plate identity, registered-cars + max-concurrent, host-in-loop; short-circuits payment.
+- [[opencv-anpr-service]] — host-side vision microservice: ANPR (plate identity) + vehicle verification (anti-plate-spoofing witness).
+- [[blocklist]] — barred plates/cards refused at entry (never at exit); signed, attributed.
+
 ## Dev environment (reference)
 - [[local-dev-workflow]] — running the stack locally; setup, the dev-hang gotchas, seed:admin.
 - [[wsl-dev-networking]] — WSL2 NAT blocks device broadcast; use mirrored mode + the gotchas after.
 
 ## Decisions
 - [[standing-decisions]] — settled decisions (stack, platform, integrity, access control, readers).
-- [[open-questions]] — 7 open items (6 procurement + JWT key choice); ESP32 device auth deferred.
+- [[open-questions]] — 9 open items (procurement + JWT key + FX + pay-station money corners); ESP32 device auth deferred.
 - [[access-controller-button-flow]] — ✅ RESOLVED: Dingtian decoupled inputs enable ticket-first entry (was a UHPPOTE/ZKTeco blocker).
 - [[autonomous-direction]] — roadmap: toward fully unmanned (no booth); reshapes threat model + fail-state.
 - [[dingtian-vs-mqtt]] — transport choice: direct HTTP/UDP now, MQTT parked until multi-lane scale.
+- [[session-model]] — business layer start: session = projection; transient-first; pay-on-foot. New event types.
+- [[vision-service]] — build a host-side ANPR + vehicle-verification service; replaces edge-LPR; scoped AGPL exception.
+- [[event-streams-split]] — split the signed business ledger (ledger_events) from unsigned device telemetry (device_events).

wiki/log.md

@@ -355,3 +355,134 @@ guarantee. Recorded in [[dingtian-relay]] (new Hardening section).
   `localAddress` set. Root cause noted as Windows-side (stray 192.168.1.x); this is the
   self-contained Linux answer.
 - Updated [[wsl-dev-networking]].
+
+## [2026-06-15] design | Business layer kickoff — parking session model
+- Pivoted from the (hardware-verified) device/integrity layer to the business domain. Wiki-first.
+- KEY DECISION: a [[parking-session]] is a PROJECTION over the signed [[append-only-event-chain]],
+  never a mutable table — a mutable sessions row with paid/owed would reopen the operator-fraud
+  hole the whole system closes. "Paid" = a signed `payment` event (unforgeable, undeletable).
+- Scope (user): mixed site, TRANSIENT-FIRST; [[permit]] holders layered as a 2nd identity source
+  that short-circuits payment. Payment = PAY-ON-FOOT / pay station (decoupled from exit; exit lane
+  only validates paid + within walk-back grace). Matches [[autonomous-direction]].
+- New signed event types designed (not yet built): `vehicle_entry`, `vehicle_exit`, `payment`,
+  `void` — extend `input_received`. Lifecycle OPEN→PAID→CLOSED (+VOIDED); overstay top-up is the
+  one genuinely stateful edge case.
+- New pages: [[parking-session]], [[tariff]] (pure/data-driven fee fn; gracePeriodExit is a real
+  pay-on-foot revenue param), decision [[session-model]]. Updated [[append-only-event-chain]],
+  [[index]]. Closes the dangling entry-flow thread from [[device-input-flow]].
+- [[permit]] drafted + RESOLVED from user input: credentials = RF tag/chip/card + QR (optical
+  reader). Car limits = two numbers: `registeredCars[]` whitelist + admin-set `maxConcurrent` (in
+  at once) — enforced as a fold over the permit's open sessions. Identity = card/QR OR matching
+  plate (either opens; card-sharing not prevented by design, caught by reconciliation). Autonomy =
+  host-in-the-loop for everything → Dingtian stays sufficient, no new controller; permit entry
+  fails closed if host down. Remaining open: reader hardware models; lapsed/revoked policy.
+- NEXT: schema (`packages/db`: permits/tariffs + session projection) + the
+  input_received→vehicle_entry flow (closes the [[device-input-flow]] thread).
+
+## [2026-06-15] design | Host-side vision service (ANPR + vehicle verification)
+- User: optionally bind camera images to an OpenCV service we build. Resolved scope: ANPR (plate →
+  `IdentitySource='lpr'`); a **separate local Python/OpenCV microservice** on the appliance (Node →
+  localhost HTTP), offline; it **replaces the dedicated edge-AI [[lpr-camera]]** (recognition on
+  ordinary Hikvision/Dahua snapshots — reuses `Snapshot.bytes`).
+- LICENSING: best ANPR/vehicle models are AGPL/commercial vs. the MIT/Apache/BSD standing rule.
+  Decision: **scoped AGPL exception** — allowed INSIDE the vision service only (separate process,
+  not linked); app stays permissive. Amended [[standing-decisions]].
+- USER ANTI-FRAUD INSIGHT: a fraudster can print a registered plate and enter with a different car.
+  → service also does **vehicle-attribute / fingerprint verification**, so the *car* reconciles, not
+  just the plate. This fills the independent-witness gap [[append-only-event-chain]] calls out:
+  plate-on-different-car = anomaly. Recognition is advisory (confidence + ticket fallback), evidence
+  (read + image) attaches to the signed event.
+- New pages: [[opencv-anpr-service]], decision [[vision-service]]. Updated [[standing-decisions]],
+  [[lpr-camera]] (host-side supersedes edge-AI), [[permit]] (plate-spoof defence),
+  [[append-only-event-chain]] (vision as witness), [[index]].
+- Open: recognizer/vehicle-model choice + accuracy; fingerprint method + anomaly threshold; appliance
+  compute (CPU vs GPU/NPU); per-camera opt-in; the still-unbuilt reconciliation logic.
+
+## [2026-06-15] design | Transient pricing — composable, versioned tariff
+- User: pricing is unknown + constantly changing → must be **admin-composable at runtime**, currency
+  selectable, FX later. Reframed [[tariff]] from "config we ship with numbers" to a first-class
+  editable entity.
+- DECISIONS: (1) rate structure = **stepped duration blocks + rolling-24h daily cap** (flat rate is
+  one block; expresses first-hour/taper/cap with no special cases); (2) overstay top-up =
+  **reprice the difference** (recompute entry→now − alreadyPaid); (3) tariffs are **effective-dated
+  immutable versions** — edits publish a new version, sessions reprice against the version in force,
+  the `payment` event records `tariffVersionId` (reproducible + fixed in the signed chain); (4)
+  **one active tariff per site**, but modelled with id/scope so multi-tariff needs no migration;
+  (5) **currency selectable (ISO 4217)**, money = `{minorUnits, currency}`, payment reserves a null
+  `fxRate` → FX-ready, **FX engine deferred** (needs offline rate source — new [[open-questions]] #8).
+- Ships with **no rate card**; owner must compose+publish one (blank = free or gated, operator
+  policy — open). Numbers in the page are illustrative, not defaults.
+- Wrote the pure integer fee algorithm into [[tariff]] (data model: `tariffs` + immutable
+  `tariff_versions`). Updated [[open-questions]] (#8 FX), [[index]].
+- NEXT: schema (`packages/db`) for tariffs/versions + permits + session projection, then the
+  composer UI + the input_received→vehicle_entry flow.
+
+## [2026-06-15] design | Shifts (manned-only) + Z-report; drop time-based token
+- Q: what happens at operator shift end? Resolved scope, deliberately small.
+- Shifts exist ONLY in manned mode — a human accountability boundary. The fully-automated/unmanned
+  system has NO shifts; the pay-station cash-collection cycle + [[reconciliation]] replace it.
+- Shift is NOT time-based: relief arrives late / no-shows / one operator forced into a double.
+  → **drop the 8h token expiry**; login valid **until explicit logout** (updated [[local-jwt-auth]];
+  code change pending). Start/End Shift are **explicit, independent of login** — one login spans many
+  shifts; a double = End then Start again, no re-login.
+- End Shift = sum signed `payment` events in the shift by tender → append a signed `shift_z_report`
+  (type already in packages/shared, chained to prior Z) → **PRINT cash total + POS total (if a POS
+  is configured)**. That's the whole human-side ask. No blind count / variance gate / manager
+  override. Fraud control stays in the signed chain + later [[reconciliation]] (catch a skim after
+  the fact, not at close). Blind-count documented as an explicit optional add-on, not built.
+- New page [[shift]]; updated [[local-jwt-auth]], [[index]].
+- Open: Z sums by payment-time (the operator who took the money) — confirm; X-report (read-only
+  mid-shift); per-operator vs per-booth vs per-site (ties to [[open-questions]] #1). `payment` event
+  needs a `tender` field (cash/card) — fold into the schema step.
+
+## [2026-06-15] design | Scope sweep — capacity, validation, reporting, integrity gaps
+- "What else can a PMS do?" — swept the full feature surface against the design; user picked the
+  in-scope gaps. New pages:
+  - [[capacity-occupancy]] — occupancy = fold over open sessions; refuse entry + drive a FULL sign
+    when full; **exit never blocked** ([[fail-state-safety]]); zone-ready; counting-drift = anomaly.
+  - [[validation-discounts]] — merchant validates a ticket → **signed discount event** applied at
+    fee time ([[tariff]]); over-validation visible to [[reconciliation]]; payment records gross/disc/net.
+  - [[reporting-analytics]] — revenue/occupancy/stay/permit/anomaly reports as projections over the
+    chain; **plate-search** (admin looks up a session by plate IF captured — honest "not captured").
+  - [[clock-integrity]] — fees depend on the host clock; offline box → backdating attack; monotonic
+    index catches reorder, clock-regression = `anomaly`, RTC + privileged-only time change.
+  - [[blocklist]] — barred plates/cards refused at **entry only**; signed + attributed.
+- Folded into existing pages: **manual overrides** = signed reason-coded events (legitimate
+  counterpart to the out-of-band-open anomaly) + **lost-ticket admin-arbitrary amount** →
+  [[parking-session]] + [[tariff]]; **backup/restore** confirmed in-scope, expanded [[open-questions]]
+  #5 (restored copy must still verifyChain; doubles as the reconciliation export).
+- NOT captured (flagged): **intercom/help-call** — user didn't select it, but it's the only human
+  fallback for an unmanned lane; revisit. Deferred roadmap: reservations, mobile app, EV, loyalty.
+- Updated [[index]].
+
+## [2026-06-15] design | Second sweep — ticket encoding + anti-passback; money corners deferred
+- More gap-hunting. New pages:
+  - [[ticket-encoding]] — the transient session key: opaque/unguessable **ticket id printed as QR**
+    by [[rongta-printer]], **scanned at pay station + exit** (new ReaderDevice/imager behind the
+    adapter); plate-as-ticket ticketless alt coexists per lane. The physical backbone of the
+    transient flow (was only implied).
+  - [[anti-passback]] — one id can't enter while it already has an OPEN session (card/ticket-passing
+    over the fence); a fold over the chain, *under* permit `maxConcurrent`. Soft (flag `anomaly`) by
+    default vs. hard (refuse); honest dependence on reliable exit detection.
+- DEFERRED (user): **receipts/VAT invoices** + **refunds/change/overpay** — depend on pay-station
+  hardware + manned/unmanned payment subsystem; recorded as [[open-questions]] #9, revisit at
+  procurement (may change what the `payment` event stores → flagged before schema).
+- Still open & load-bearing: **lane topology** (#1) — not resolved; scopes sessions/occupancy/shifts.
+- Updated [[open-questions]] (#9), [[index]].
+
+## [2026-06-15] decision | Split signed business ledger from device telemetry
+- User correction before schema: the `events` table conflated TWO things — the anti-fraud business
+  ledger AND device telemetry (button pushes as `input_received`). Split them.
+- `ledger_events` (rename of `events`): signed, hash-chained, ATECC608-signed business facts only
+  (vehicle_entry/exit, payment, void, shift_z_report + witness barrier_open_command/observed,
+  anomaly). Reconciliation + session/tariff/occupancy projections run on this.
+- `device_events` (new, [[device-events]]): UNSIGNED hardware telemetry (relay fired, paper-out,
+  camera offline, reader read, raw input edges); high-volume, may rotate/prune; never reconciled.
+- A raw button press is telemetry → device_events; the entry flow then mints a SIGNED vehicle_entry.
+  So `input_received`-as-signed-event is dropped (was transitional). No prod chain data exists, so
+  the rename/restructure is safe now (no signatures to invalidate).
+- New: decision [[event-streams-split]], concept [[device-events]]; updated [[append-only-event-chain]]
+  (two streams + as-built-vs-pending), [[index]].
+- NEXT (schema): rename events→ledger_events; add device_events; split ParkingEventType in shared;
+  then tariffs/versions, permits, blocklist, sessions projection. EventLog/canonicalize/verifyChain
+  + /api/events follow the rename (code refactor, separate from this wiki commit).