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).

ui/README.md

@@ -35,7 +35,7 @@ The **native (Capacitor) build** additionally reads `VITE_DICT_VERSION` (the bun
 the offline path requests, matching the packaged DAWGs), `VITE_PAYMENTS_DISABLED=1` (hide in-app purchases
 in the RuStore MVP), `VITE_RUSTORE_URL` (the update overlay's store target; empty until published) and
 `VITE_APP_VERSION` (`git describe --tags` → the `X-Client-Version` gate header) — all wired by
-`.gitea/workflows/android-build.yaml`; see `ANDROID_PLAN.md`.
+`.gitea/workflows/android-build.yaml`.
 
 The build has **two entries**: the game SPA (`index.html`, served at `/app/` and
 `/telegram/`) and a lightweight landing page (`landing.html`, served at `/`).