feat(tariff): V2 — legacy-parity pricing (time-of-day, category, seasonal, flat)

Bring the legacy ParkSQL2017 pricing BREADTH onto our engine while keeping
integer-minor-unit money + immutable signed versions (rejecting legacy's
float money / mutable rows). TariffStructure becomes a discriminated union:
V1 = the original bare ladder (UNCHANGED, verbatim algorithm, golden-
regression-tested against the live version); V2 = {version:2, tz, shared
knobs, defaultCard, windowedCards[]} where each card is flat OR a block
ladder and may be scoped by wall-clock hour window / day-of-week / date
range / vehicle category.

computeFeeV2 prices by stepping one increment at a time, advancing the
ladder by ELAPSED minutes (continuous) while selecting the active card by
WALL-CLOCK time in the version's FROZEN tz. Decisions: tz is a per-site
setting (site_config.timezone, default Europe/Tirane) stamped server-side
into each version on publish — never the host clock (reproducibility);
default-card cap governs a mixed day; precedence = specificity
(date>dow>hour) -> priority -> name (total, order-independent), validation
rejects ambiguous ties; category = a card FIELD, frozen in the signed
vehicle_entry payload (site_config.default_vehicle_category default), read
at both pricing call-sites.

Composer: default card front-and-centre (flat/ladder toggle), tiers under
an "Advanced" disclosure; emits BARE V1 when no tiers (back-compat). DB:
migrations 0005 (timezone) + 0006 (default_vehicle_category). Stood up
vitest in @parking/shared (was zero tests on the ledger-feeding fee fn);
36 tests incl. golden V1 regression, happy-hour/overnight/dow/flat/category/
cap edges, precedence shuffle-invariance, Europe/Tirane DST determinism,
validation matrix — all green. No event-chain change.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

apps/server/src/entry-flow.ts

@@ -10,6 +10,7 @@ import {
   type TicketData,
   type TicketHeader,
 } from "@parking/devices";
+import { DEFAULT_VEHICLE_CATEGORY } from "@parking/shared";
 import type { FastifyBaseLogger } from "fastify";
 import type { DeviceInputEvent } from "./device-events.js";
 import { getOccupancy } from "./occupancy.js";
@@ -113,12 +114,24 @@ export class EntryFlow {
     }
 
     // 2. SIGN the vehicle_entry — BEFORE the relay fires (the core invariant).
+    //    `category` is FROZEN here (in the signed payload) so the tariff prices and
+    //    later reprices the same way at exit. Today every transient takes the SITE
+    //    default category (operator policy, site_config.default_vehicle_category;
+    //    falls back to the shared DEFAULT_VEHICLE_CATEGORY). Per-relay capture (a
+    //    "bus lane" relay, mirroring how direction is per-relay in device-resolve.ts)
+    //    is the future seam — source it from `resolved` then. A V1/no-category tariff
+    //    ignores it; only V2 category cards consult it.
+    const cfg = this.#db.select().from(siteConfig).where(eq(siteConfig.id, 1)).get();
+    const category =
+      cfg?.defaultVehicleCategory && cfg.defaultVehicleCategory.length > 0
+        ? cfg.defaultVehicleCategory
+        : DEFAULT_VEHICLE_CATEGORY;
     await this.#log.append({
       type: "vehicle_entry",
       direction: "entry",
       source: "ticket",
       identity: ticketId,
-      payload: { sessionRef: ticketId, ticketPrinted: true },
+      payload: { sessionRef: ticketId, ticketPrinted: true, category },
       occurredAt: issuedAt,
     });