feat(offline): implicit net-state model, two-tier version gate, unified lobby

Land the offline-model redesign (ANDROID_PLAN.md O1-O7): replace the explicit offline toggle with a single detected net-state machine, unify the lobby, and add a two-tier client-version gate. Contour-safe: both version vars empty => dormant, and the wire change is additive, so web/pwa/vk/tg behaviour is unchanged unless the gate is deliberately configured.

O1 pure net-state reducer (test-first). O2 reactive store + event wiring (connection/offline become thin shims; +@capacitor/network). O3 remove the offline toggle + migrate the pref. O4 two-tier gate: hard update_required degrades to an offline Update/Play-offline notice (not terminal); soft GATEWAY_RECOMMENDED_CLIENT_VERSION -> X-Update-Recommended nudge. O5 unified lobby (device-local + greyed-from-cache server games; self-set identity; closes G-step-0). O6 create flows (with-friends online/offline segment + offline dict guard). O7 docs (ARCHITECTURE, FUNCTIONAL +_ru, TESTING, deploy/README).

Also disable the manual android-build CI workflow for now (rename to .disabled); the Android APK release comes later.

Tests: gateway go green, svelte-check 0/0, vitest 617, e2e 122/122 (chromium + webkit).

docs/FUNCTIONAL.md

@@ -277,22 +277,25 @@ add-friend are off. AI games are **practice** — they never count toward a play
 statistics.
 
 ### Offline mode
-An installed web PWA signed in with a confirmed email can switch to a deliberate **offline mode**
-(Settings → Play mode). Offline, the app never touches the network: the header turns blue with an
-*Offline* chip, the lobby lists only the games stored on the device, and online-only surfaces are
-disabled or hidden (the Stats tab; the *random opponent* option in New Game).
-A New Game against the robot creates a device-local **vs_ai** game — it
-plays entirely in the browser with no backend. Local games are kept on the device, visible only in
-offline mode, and never sync to the account. So a game can be created and played with no connection,
-the app quietly preloads the dictionaries for the player's enabled variants while still online, and
-(once installed) launches from a precached shell even with no network. Switching **to** offline first
-checks that the enabled variants' dictionaries are on the device — if any are missing it fetches them
-and waits briefly, and if they cannot be readied it stays online with a short *needs internet* note
-(the download keeps running in the background, so a later switch is instant). The mode is
-device-scoped and sticky across launches.
+The app plays **offline automatically** — there is **no on/off switch**. When it cannot reach the
+server the header turns blue with an *Offline* chip and play is confined to games on the device; a
+momentary blip is ridden out as a quiet *"Connecting…"* (it never drops you offline), and when the
+connection returns the app goes back online on its own with a brief *back online* toast. Offline, the
+app never touches the network.
 
-Offline, New Game's **with friends** starts a **local pass-and-play** game for 2-4 people sharing one
-device. You first set a **host (leader) password** — a 4-digit PIN entered on a lock-screen-style
+The **lobby stays unified**: your device-local games are active, while your server games are still
+listed but **greyed out** — visible but un-openable until you are back online (a tap explains why).
+Online-only surfaces (the Stats tab) are disabled and invitations are hidden while offline. A New Game
+against the robot creates a device-local **vs_ai** game that plays entirely on the device with no
+backend; local games are kept on the device and never sync to the account, so a game can be created and
+played with no connection. The app quietly preloads the dictionaries for the player's enabled variants
+while still online, and (once installed, or on the native app) launches from bundled/precached data even
+with no network; if a variant's dictionary is not available offline, creating that game is disabled with
+a short note.
+
+New Game's **with friends** offers a choice — **invite a friend** to play online, or a **local
+pass-and-play** game for 2-4 people sharing one device; with no network only pass-and-play is available.
+In pass-and-play you first set a **host (leader) password** — a 4-digit PIN entered on a lock-screen-style
 keypad; until it is set the player rows stay locked. The app then asks whether you are playing too —
 if so you take the first seat with your profile name. You name each player (2 to 4; add or remove
 rows, where a removal asks for the leader password) and may give any seat its **own optional PIN**.
@@ -305,14 +308,18 @@ pass-and-play game. A game that finishes normally is saved to the offline lobby
 deleting any pass-and-play game — running or finished — from the lobby asks for the leader password,
 so no one can wipe a game the moment they have moved.
 
-The app also **enters offline mode on its own** when it cannot reach the network. On a cold launch
-with no connection it switches to offline for that session; when the device is online but the gateway
-stays silent for a few seconds it asks first — *No connection. Switch to offline mode?*, with
-**Switch** (go offline) or **Wait for network** (keep retrying online). While the app is open, losing
-the network — airplane mode — switches to offline automatically, and restoring it returns online by
-itself. A self-entered offline is temporary: it reverts to online the moment the network is back, and
-the next launch re-checks. A **deliberate** offline — the Settings toggle, or **Switch** in that
-dialog — is the player's choice: it is kept, and never undone automatically.
+Going offline and coming back are both **automatic**. On a cold launch with no connection the app
+starts straight in the offline lobby; while it is open, losing the network — airplane mode — turns it
+offline on its own, and restoring the network returns it online by itself. There is no dialog and no
+switch to remember: a brief drop is ridden out quietly and only a sustained loss turns the chrome
+offline, so you are never interrupted for a hiccup.
+
+### Staying up to date
+When a new client version is required, the app does not lock you out. On the **native** app a
+too-old build shows a notice with **Update** (opens the store) and **Play offline** (dismiss and keep
+playing your on-device games); on the web it offers **Update** (reload) instead. A softer,
+non-blocking **"update available"** banner appears in the lobby when a newer — but not yet
+required — version exists; you can update or dismiss it, and play continues either way.
 
 ### Native app (Android)
 The game also ships as a standalone **Android app** (first on **RuStore**), a packaged build of the same