Initial scaffold: Turborepo monorepo + design wiki

Turborepo (pnpm workspaces) with all dependencies pinned to latest
mutually-compatible versions: turbo 2.9, TypeScript 6, Fastify 5,
React 19, Vite 8, better-sqlite3 12 + Drizzle ORM 0.45.

Layout:
- apps/server   Fastify backend (local JWT auth + role guard, /health)
- apps/web      React 19 + Vite 8 operator SPA
- packages/db   Drizzle schema on SQLite/WAL; append-only events + users
- packages/devices  reader/printer/relay adapter interfaces (intent-only relay)
- packages/shared   shared domain types

Architecture constraints from the design wiki are encoded in the scaffold:
append-only hash-chained + signed event log, device-agnostic adapters,
"a barrier is not a door" (relay expresses intent only), fully-local
offline-first auth.

wiki/ is an LLM-maintained Obsidian knowledge base (28 pages) ingested
from the architecture & design notes, with its own maintenance schema.

Verified: pnpm install, full turbo build (5/5), server boots and serves
/health, drizzle-kit generates the initial migration.

wiki/concepts/threat-model.md

@@ -0,0 +1,37 @@
+---
+type: concept
+tags: [parking, security, foundational]
+sources: [parking-system-architecture]
+updated: 2026-06-14
+---
+
+# Threat Model
+
+The **second foundational force** (with [[offline-first]]). The central insight is a
+**reframing of who the adversary is**. (See [[parking-system-architecture]] §3.)
+
+## The key reframing
+
+Early thinking focused on protecting the database **at rest** — SQLCipher, LUKS, BitLocker,
+TPM-sealed keys. All of that defends against **an outsider who steals the machine or boots from
+external media**.
+
+That is the **wrong primary threat**. The most likely adversary is the **legitimate operator at
+the booth**. While the app runs, the database is decrypted in memory and the operator has full
+authorised access *through the app*. Encryption does nothing against the classic parking fraud:
+**take the cash, then void/delete the entry/exit record so the books balance.**
+
+## Consequences
+
+The controls that actually address insider/operator fraud are different in kind:
+
+- **[[append-only-event-chain]]** — events appended, never edited/deleted; a "void" is itself a
+  recorded event, hash-chained, and **[[atecc608]]-signed** (unforgeable).
+- **[[reconciliation]]** against an authority the operator can't alter — *this is what remote
+  sync really is*: a fraud-control mechanism, not just a backup.
+- **[[disk-os-hardening]]** still worthwhile (defeats boot-from-USB) but **not the main event**;
+  with LUKS in place, SQLCipher is optional defence-in-depth.
+
+The same reframing recurs at the device layer: the [[uhppote-controller]]'s real problem is
+unauthenticated commands ([[uhppote-udp-protocol]]), addressed by detection
+([[event-log-ingestion]]) or prevention ([[esp32-custom-controller]]).