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, the wire change is additive, so web/pwa/vk/tg behaviour is unchanged unless the gate is deliberately configured.

O1 net-state reducer (test-first). O2 store + wiring (connection/offline 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.

Deploy/CI: wire the version gate through the deploy (GATEWAY_MIN_CLIENT_VERSION + GATEWAY_RECOMMENDED_CLIENT_VERSION as plain unprefixed vars via compose + ci.yaml + prod-deploy.yaml + write-prod-env.sh + .env.example) so the gate is live when set (test-contour commit-hash version fails open; empty => dormant). Disable the manual android-build CI workflow for now (rename .disabled). Bump the app bundle budget 127->130 KB for the added always-loaded wiring. Fix the UI Docker stage (gateway/Dockerfile): install --ignore-scripts so the Alpine/musl SPA build no longer tries to native-build sharp (a local android:assets tool, unused in the image); esbuild's binary is an optional dep so Vite still builds.

Tests: gateway go green (two-tier gate over a real HTTP handler); docker build of the landing + gateway targets green locally; compose --no-interpolate confirms the gateway env; svelte-check 0/0, vitest 617, e2e 122/122 (chromium + webkit).

ui/src/App.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
   import { onMount } from 'svelte';
   import { cubicOut } from 'svelte/easing';
-  import { app, bootstrap, resolveOfflinePrompt } from './lib/app.svelte';
+  import { app, bootstrap } from './lib/app.svelte';
   import { router, type RouteName } from './lib/router.svelte';
   import { t } from './lib/i18n/index.svelte';
   import { initNativeShell } from './lib/native';
@@ -145,21 +145,6 @@
 <MaintenanceOverlay />
 <UpdateOverlay />
 
-<!-- Cold-start "no connection" dialog: the reachability check timed out with the network interface
-     reportedly online, so it is ambiguous. The player chooses to go offline (play local vs_ai) or to
-     keep trying to connect. bootstrap awaits this choice (app.offlinePrompt). -->
-{#if app.offlinePrompt}
-  <div class="offprompt" role="dialog" aria-modal="true">
-    <div class="card">
-      <p class="msg">{t('offline.promptTitle')}</p>
-      <div class="acts">
-        <button class="opt primary" onclick={() => resolveOfflinePrompt(true)}>{t('offline.promptYes')}</button>
-        <button class="opt" onclick={() => resolveOfflinePrompt(false)}>{t('offline.promptNo')}</button>
-      </div>
-    </div>
-  </div>
-{/if}
-
 {#if routeIsLobby && !app.splashDone && !app.blocked && !app.bootError && !app.launchError}
   <Splash />
 {/if}
@@ -169,49 +154,6 @@
 {/if}
 
 <style>
-  /* The cold-start "no connection" dialog — a centred card over a scrim, above the splash. */
-  .offprompt {
-    position: fixed;
-    inset: 0;
-    z-index: 100;
-    display: flex;
-    align-items: center;
-    justify-content: center;
-    background: rgba(0, 0, 0, 0.5);
-    padding: var(--pad);
-  }
-  .offprompt .card {
-    background: var(--bg-elev);
-    border: 1px solid var(--border);
-    border-radius: var(--radius-sm);
-    padding: 20px;
-    max-width: 320px;
-    width: 100%;
-    text-align: center;
-  }
-  .offprompt .msg {
-    margin: 0 0 16px;
-    font-size: 1rem;
-    color: var(--text);
-  }
-  .offprompt .acts {
-    display: flex;
-    flex-direction: column;
-    gap: 8px;
-  }
-  .offprompt .opt {
-    padding: 11px 16px;
-    border: 1px solid var(--border);
-    border-radius: var(--radius-sm);
-    background: var(--surface);
-    color: var(--text);
-    font-size: 0.95rem;
-  }
-  .offprompt .opt.primary {
-    background: var(--accent);
-    color: var(--accent-text);
-    border-color: var(--accent);
-  }
   .splash {
     height: 100%;
     display: grid;