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/decisions/open-questions.md

@@ -0,0 +1,30 @@
+---
+type: decision
+tags: [parking, decisions, open]
+sources: [parking-system-architecture]
+updated: 2026-06-14
+status: open
+---
+
+# Open Questions / Next Steps
+
+**Not yet decided**, and they drive everything else — settle before procurement. (See
+[[parking-system-architecture]] §10.)
+
+1. **Lane topology.** One host per lane, or one central host driving networked devices in each
+   lane? Decides how many controllers, printers, UPSs, and [[sqlite]] instances exist, and the
+   failure blast radius. (A single central host is a single point of failure for *all* lanes.)
+2. **Failure modes.** Define per direction what happens to barriers on host/power/network loss —
+   particularly **fail-open on exit** for egress safety. Currently unaddressed. See
+   [[fail-state-safety]].
+3. **Payment subsystem.** Manned booth (P2PE terminal + cash drawer) vs unmanned pay station;
+   confirm **PCI scope is kept out of the application** via a standalone certified terminal
+   (see [[bom]]).
+4. **Reconciliation channel.** Even if "offline," establish *some* periodic path (USB, hotspot,
+   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**.
+6. **Secure-element integration.** Confirm [[atecc608]] wiring/usage on both the host (event
+   signing) and, if pursued, the custom controller (command authentication — see
+   [[esp32-custom-controller]]).