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).

deploy/README.md

@@ -118,7 +118,8 @@ without it Docker's resolver handles `otelcol`, `gateway` and `api.telegram.org`
 | `GATEWAY_BLOCKLIST_ENABLED` | variable | `false` | Enable the community IP blocklist at the edge (prod-only, same real-client-IP reason as the ban). Requires `GATEWAY_BLOCKLIST_URL`. Opt-in via `PROD_GATEWAY_BLOCKLIST_ENABLED` after verifying the feed. |
 | `GATEWAY_BLOCKLIST_URL` | variable | _(empty)_ | The curated CIDR feed to fetch (Spamhaus DROP). Required when enabled; refreshed every few hours and dropped fail-open once stale (48h). `PROD_GATEWAY_BLOCKLIST_URL`. |
 | `GATEWAY_BLOCKLIST_ALLOW` | variable | _(empty)_ | Comma-separated never-block set (CIDRs / bare IPs — own infra, monitoring) the feed can never block. `PROD_GATEWAY_BLOCKLIST_ALLOW`. |
-| `GATEWAY_MIN_CLIENT_VERSION` | variable | _(empty)_ | Minimum client build the gateway will serve — the native client-version gate (ARCHITECTURE.md §2). Empty ⇒ **dormant** (every build served, the web default). Set it to the release `vMAJOR.MINOR.PATCH` in the **same** rollout that ships an incompatible wire change, so an older bundled APK is turned away with an *update required* signal instead of failing blind. Validated at load; a non-empty unparseable value fails startup. |
+| `GATEWAY_MIN_CLIENT_VERSION` | variable | _(empty)_ | **Hard** tier of the client-version gate (ARCHITECTURE.md §2). Minimum client build the gateway will serve. Empty ⇒ **dormant** (every build served, the web default). Set it to the release `vMAJOR.MINOR.PATCH` in the **same** rollout that ships an incompatible wire change, so an older bundled APK is turned away with an *update required* signal instead of failing blind — the client then degrades to an offline "Update / Play offline" notice, not a hard lockout. Validated at load; a non-empty unparseable value fails startup. |
+| `GATEWAY_RECOMMENDED_CLIENT_VERSION` | variable | _(empty)_ | **Soft** tier of the client-version gate (ARCHITECTURE.md §2). A build at or above `GATEWAY_MIN_CLIENT_VERSION` but **below** this is served normally, but every gated `Execute` response carries an additive `X-Update-Recommended: 1` header ⇒ the client shows a dismissable *update available* nudge (play continues). Empty ⇒ off. Validated at load: unparseable, or **below** `GATEWAY_MIN_CLIENT_VERSION`, fails startup. Bump it (ahead of `MIN`) to nudge upgrades before a hard cut-over. |
 | `VITE_GATEWAY_URL` | variable | _(empty)_ | UI build-arg: gateway origin; empty = same-origin (the usual single-origin deploy). |
 | `SMTP_RELAY_HOST` | variable (shared) | _(empty)_ | Selectel SMTP relay host for confirm-code email. Empty leaves the backend on the log mailer (email disabled) — the contour still boots. One relay for every contour (limit 100 msgs / 5 min). |
 | `SMTP_RELAY_PORT` | variable (shared) | `465` | Relay port. No client certificate is needed (the server cert is validated against the system roots). |