feat(desktop): Tauri v2 kiosk shell — maximized window, prod right-click block, auto-update + code-signing

Add apps/desktop, a thin Tauri v2 shell wrapping the SAME @parking/web SPA so
the desktop and browser UIs never drift: dev loads the Vite dev server (HMR),
prod bundles the web app's dist/. No business logic in the shell (device/auth/
ledger stay in @parking/server); deny-by-default capabilities.

apps/web (single UI source of truth):
- lib/origin.ts: centralize the backend origin (API_BASE/apiUrl/wsUrl from
  VITE_API_BASE); no-op in the browser, lets the desktop build target Fastify.
- lib/kiosk.ts: block the right-click context menu in PROD only (dev keeps it +
  devtools).
- lib/desktop-updater.ts: prompt-on-update auto-update (no-op in browser/offline)
  → downloadAndInstall + relaunch; i18n update.* keys (sq+en).
- .env.production: VITE_API_BASE wired to the Fastify origin for the bundle.

Desktop:
- window starts maximized (not fullscreen — operator keeps OS access).
- auto-update via tauri-plugin-updater + -process; self-hosted endpoint is a
  PLACEHOLDER to fill in. Updater keypair: pubkey embedded in tauri.conf.json;
  private key + password kept OUTSIDE the repo (~/.parking-updater-keys) and as
  TAURI_SIGNING_* build secrets.
- Turbo build is a no-op; the real signed bundle is `pnpm --filter
  @parking/desktop bundle` (verified → .deb/.rpm/.AppImage + .sig signatures).

Verified: cargo check clean; turbo run build lint 14/14 green; i18n parity holds;
no key/sig/bundle artifacts in the repo.

Wiki (security + desktop analysis recorded alongside):
- new concepts/tpm.md (TPM 2.0: how it works, sealed-LUKS auto-unlock + non-
  extractable signing key, limits — live-root, bus-sniff — TPM-vs-ATECC608 by
  platform).
- new decisions/desktop-shell-tauri.md (Tauri v2 over Electron; best-case Ubuntu
  26.04 LTS, worst-case Windows+WSL → kiosk browser; full as-built).
- pull-the-disk attack trace on append-only-event-chain; ATECC608 not-in-a-PC
  caveat; cross-links from disk-os-hardening / threat-model.
- open-questions #11 (appliance WebKitGTK), #12 (TPM hardening impl), #13
  (startup verifyChain self-check); index/overview/log/standing-decisions.

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

apps/web/src/lib/origin.ts

@@ -0,0 +1,30 @@
+// Where the SPA reaches the Fastify backend.
+//
+// In a browser (dev via the Vite proxy, or prod where Fastify serves the built
+// SPA) this is EMPTY — requests stay relative (`/api/...`) and same-origin, so
+// nothing changes. The Tauri desktop shell (apps/desktop) serves the bundled
+// SPA from `tauri://localhost`, which has no backend and no proxy; there we set
+// VITE_API_BASE to the appliance's Fastify origin (e.g. http://127.0.0.1:3000)
+// at build time so /api and the live WS feed resolve to the real server.
+//
+// Keep this the SINGLE source for the backend origin — api.ts and the live-feed
+// WebSocket both read it, so the web app and the desktop shell stay identical
+// except for this one build-time value.
+
+/** Backend HTTP origin, no trailing slash. Empty string = same-origin/relative. */
+export const API_BASE: string = (import.meta.env.VITE_API_BASE ?? "").replace(/\/$/, "");
+
+/** Resolve an API path to a full URL (or a relative path when API_BASE is empty). */
+export function apiUrl(path: string): string {
+  return API_BASE ? `${API_BASE}${path}` : path;
+}
+
+/** Build the ws:// or wss:// URL for the backend's live feed. Uses API_BASE when
+ *  set (Tauri), else the page origin (browser). */
+export function wsUrl(path: string): string {
+  if (API_BASE) {
+    return `${API_BASE.replace(/^http/, "ws")}${path}`;
+  }
+  const proto = window.location.protocol === "https:" ? "wss:" : "ws:";
+  return `${proto}//${window.location.host}${path}`;
+}