docs(android): bake the version gate, identity model + native build into the docs

ARCHITECTURE §2 (client-version gate + frozen wire contract + gate x offline),
§3 (local-guest / server-guest / reconciliation identity), §13 (native Capacitor
build). FUNCTIONAL (+_ru) a new "Native app (Android)" domain. TESTING (the
clientver/gate Go tests, the native/update e2e + retry mapping, and the manual
on-device Android smoke checklist). deploy/README (GATEWAY_MIN_CLIENT_VERSION +
the wire-break bump discipline + the Android build/release runbook). ui/README
native VITE_* vars. Mark F done in ANDROID_PLAN.md.

ui/README.md

@@ -31,6 +31,11 @@ enables the "Link Telegram" web sign-in (the Login Widget) — inert until the s
 domain is registered with BotFather (`/setdomain`); `VITE_TELEGRAM_LINK` is the
 friend-invite Mini App link for the single bot (full URL `https://t.me/<bot>/<app>`).
 `VITE_TELEGRAM_GAME_CHANNEL_NAME` is the "Play in Telegram" link shown on the landing page.
+The **native (Capacitor) build** additionally reads `VITE_DICT_VERSION` (the bundled-dictionary version
+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`.
 
 The build has **two entries**: the game SPA (`index.html`, served at `/app/` and
 `/telegram/`) and a lightweight landing page (`landing.html`, served at `/`).