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/uhppote-vs-esp32.md

@@ -0,0 +1,31 @@
+---
+type: concept
+tags: [parking, comparison, access-control, security]
+sources: [parking-system-architecture]
+updated: 2026-06-14
+---
+
+# UHPPOTE vs. Custom ESP32 — Detection vs. Prevention
+
+A head-to-head on the [[trust-boundary]] fork: the off-the-shelf [[uhppote-controller]] versus
+the [[esp32-custom-controller]]. (Synthesized from [[parking-system-architecture]] §6–7.)
+
+| | [[uhppote-controller]] | [[esp32-custom-controller]] |
+| --- | --- | --- |
+| **Trust boundary** | The network | The device |
+| **Security posture** | Tamper-**evident** (detection) | Tamper-**proof** (prevention) |
+| **Command auth** | None — [[uhppote-udp-protocol]] is open UDP | [[challenge-response-auth]] (asymmetric sigs) |
+| **Key mitigation** | [[network-isolation]] (mandatory) + [[event-log-ingestion]] | [[atecc608]] holds non-extractable key; controller stores only a public key |
+| **Firmware** | Manufacturer-only; not customizable | You own it (tiny + auditable) |
+| **Cost / effort** | Cheap, off-the-shelf, available now | Build + firmware reliability, EMC/surge, field maintenance |
+| **Replay/forgery on the wire** | Possible — contained only by isolation | Defeated by fresh per-command nonce |
+| **Safety** | Barrier operator owns it ([[barrier-not-a-door]]) | Same + explicit [[fail-state-safety]] |
+
+## Bottom line
+
+- The UHPPOTE is the **current choice**: good enough as a detection/audit layer **when only the
+  host can reach it** (isolation) and every event lands in the [[append-only-event-chain]].
+- The ESP32 is the **documented upgrade** when you need a control path that holds even against an
+  attacker on the wire. They're **mixable per lane**.
+- Both still rely on host-side integrity ([[append-only-event-chain]]) and external
+  [[reconciliation]] as the ultimate anti-fraud control.