feat(beta): phase 5 — the app page and the closed-beta signup

Builds `/app/` and `/beta/`, the SQLite signup store, the rate limiting and the
export CLI of PLAN.md §8, and adds this repository's first test suite.

Four decisions of record, D26–D29 (§8, "How phase 5 built the app and the beta"):

- D26 — the screenshot slot ships empty, reserved for phase 9. §10 promised
  `/app/` "the 14 existing screenshots"; they are a July trusted-device smoke
  test against an unseeded dev instance, captured before the theming work, and
  five of the fourteen are two-factor prompts. Shipping them would break D4.
  Phase 9 already builds the rig, so it gains an emulator pass.
- D27 — the public demo is the tester target. `ConnectScreen.kt` gates the whole
  app on a validated deployment address, so a tester needs somewhere to point it.
  The beta therefore waits on the demo VM, and the page says so.
- D28 — `/beta` handles its own POST; there is no `/api/beta-signup`. An endpoint
  cannot report a validation error without JavaScript. §6's diagram is amended.
- D29 — the APK and the beta get equal billing, and the APK link is off:
  `androidApk.serviceable` is false because the published v0.5.0 build does not
  work. The panel stays and states that plainly rather than being removed.

Three mechanisms the plan did not anticipate:

- `liveBrand()` — a server-rendered page never passes through the boot rewrite,
  so `/beta` reads the mounted brand.json itself. Pasting the Play opt-in URL in
  takes effect on the next request rather than the next restart.
- `checkLinks.mjs` derives on-demand routes from `prerender = false` in the
  source. A PLANNED_ROUTES entry would have been wrong: its reverse check fires
  when a route has been built, and an on-demand route never produces a file, so
  the entry could never rot out.
- `npm test` — the five existing checks all read built output, and none of this
  logic appears there. A honeypot can stop working and leave the build identical.

Also: `checkFacts.mjs` gains the APK assets and `minSdk`, and learns that RFC 2606
reserved domains are not contact addresses; the D13 rule is otherwise unchanged.

Verified end to end against the built server: every outcome renders with no
JavaScript, cross-origin POSTs are refused, a mounted opt-in URL appears without
a restart, and the export CLI round-trips.

Co-Authored-By: Claude <noreply@anthropic.com>

.gitea/workflows/pr-checks.yml

@@ -41,6 +41,20 @@ jobs:
       - name: Types
         run: npm run check
 
+      - name: Unit tests
+        # PLAN.md §8 — the beta signup's decision path: honeypot, form token, timing, rate
+        # limit, cap, validation, duplicate, removal.
+        #
+        # The first thing in this repository that the other checks cannot see. They all read
+        # the built output, and none of this appears there: a honeypot that has stopped
+        # working produces a build that is identical in every way to one where it works.
+        #
+        # The test file is NAMED rather than the directory passed. `node --test test/` fails
+        # on Node 22 with MODULE_NOT_FOUND — directory mode is not portable across the
+        # versions this org runs, and this workflow pins 22 while developers are on 24, so
+        # the shorter form would pass locally and break only here.
+        run: npm test
+
       - name: Production build
         run: npm run build