chore(android): de-anchor ANDROID_PLAN.md from the docs, re-enable the APK workflow

Reword every code comment and doc that referenced ANDROID_PLAN.md or its stage anchors (§E, G-step-0, O1) so the living docs no longer depend on the plan file: .claude/CLAUDE.md, deploy/README.md, docs/ARCHITECTURE.md, docs/TESTING.md, ui/README.md, ui/android/.gitignore, ui/e2e/native.spec.ts, ui/src/lib/netstate.ts.

Re-enable the manual signed-APK workflow (android-build.yaml.disabled -> android-build.yaml; the CI host already has the Android SDK; workflow_dispatch-only, so it does not auto-run on this PR). Add docs/ICONS.md — the single-master icon/logo format reference (web, PWA, Android, future iOS, store listings).

docs/TESTING.md

@@ -40,7 +40,7 @@ tests or touching CI.
   in the **offline guest lobby** (not `/login`), plays a local vs_ai move from the **bundled** dawg tier
   (`playwright.config.ts` bundles the dicts into `dist-e2e/dict/`), starts a hotseat game, and drives
   `window.__native.reconcile()` to prove online lights up — the device-local game stays listed in the
-  **unified lobby** (closing G-step-0) — and Profile hides the Telegram/VK link buttons.
+  **unified lobby** — and Profile hides the Telegram/VK link buttons.
   The **version-gate** spec (`e2e/update.spec.ts`) drives the `__update` hook to prove both tiers — the
   hard *Update / Play offline* notice (and that "Play offline" drops into the offline lobby) and the soft
   dismissable *update available* nudge in the lobby; `retry.test.ts` covers the `FailedPrecondition →