Stage 9: Telegram integration (connector side-service, Mini App, out-of-app push)

New platform/telegram connector (own container, bot token only there):
- go-telegram/bot long-poll loop: /start deep-links + Mini App launch button.
- gRPC API pkg/proto/telegram/v1 (Telegram service): ValidateInitData, Notify
  (renders a localized message + deep-link button), SendToUser/SendToGameChannel
  (admin, wired in Stage 10). Generic methods are platform-agnostic (external_id).
- Bot API base override for Telegram's test environment; Dockerfile + compose
  (VPN sidecar, no public ingress); README.

Gateway:
- initData validation relocated from the gateway into the connector; the gateway
  calls ValidateInitData over gRPC (GATEWAY_CONNECTOR_ADDR), drops the bot token,
  and deletes internal/auth.
- Out-of-app push: runPushPump routes events whose recipient has no live in-app
  stream to connector.Notify, gated by /internal/push-target + the in-app-only
  flag (race-free de-dup); HasSubscribers added to the push hub.

Backend:
- Migration 00007 accounts.notifications_in_app_only (default true) + jetgen.
- ProvisionTelegram seeds a new account's language/display name from the launch
  fields; IdentityExternalID reverse lookup; /internal/push-target handler.

UI:
- Telegram Mini App launch: detect initData, apply themeParams, authTelegram,
  route the deep-link start_param (g/i/f); /telegram/ guard redirects outside
  Telegram. Vite relative base + telegram-web-app.js. In-app-only profile toggle;
  share-to-Telegram link for a friend code. Vitest + Playwright coverage.

Wire/docs/CI: fbs Profile/UpdateProfileRequest gain notifications_in_app_only
(Go + TS); go.work uses ./platform/telegram; go-unit.yaml covers it; PLAN,
ARCHITECTURE, FUNCTIONAL (+ru), UI_DESIGN, READMEs updated.

ui/src/lib/app.svelte.ts

@@ -8,7 +8,9 @@ import { gateway } from './gateway';
 import { GatewayError } from './client';
 import { navigate, router } from './router.svelte';
 import { errorKey, localeFrom, setLocale, t, type Locale } from './i18n/index.svelte';
-import { applyReduceMotion, applyTheme, type ThemePref } from './theme';
+import { applyReduceMotion, applyTelegramTheme, applyTheme, type ThemePref } from './theme';
+import { insideTelegram, onTelegramPath, telegramLaunch } from './telegram';
+import { parseStartParam } from './deeplink';
 import { clearSession, loadPrefs, loadSession, saveSession, savePrefs } from './session';
 import type { BoardLabelMode } from './boardlabels';
 
@@ -144,6 +146,28 @@ export async function bootstrap(): Promise<void> {
     setLocale(guess);
   }
 
+  // Telegram Mini App launch: apply the platform theme, authenticate via initData,
+  // and route any deep-link start parameter. On the dedicated /telegram/ entry path
+  // outside Telegram (no initData), refuse to render and send the visitor to the
+  // site root.
+  if (onTelegramPath() && !insideTelegram()) {
+    if (typeof location !== 'undefined') location.replace('/');
+    return;
+  }
+  if (insideTelegram()) {
+    const launch = telegramLaunch();
+    if (launch.theme) applyTelegramTheme(launch.theme);
+    try {
+      await adoptSession(await gateway.authTelegram(launch.initData));
+      await routeStartParam(launch.startParam);
+    } catch (err) {
+      handleError(err);
+      navigate('/login');
+    }
+    app.ready = true;
+    return;
+  }
+
   const saved = await loadSession();
   if (saved) {
     await adoptSession(saved);
@@ -154,6 +178,32 @@ export async function bootstrap(): Promise<void> {
   app.ready = true;
 }
 
+/**
+ * routeStartParam navigates a Telegram deep-link start parameter to its target: a
+ * specific game, the friends screen with a friend-code redemption, or the lobby
+ * (where invitations surface as a badge).
+ */
+async function routeStartParam(param: string): Promise<void> {
+  const link = parseStartParam(param);
+  switch (link.kind) {
+    case 'game':
+      navigate(`/game/${link.id}`);
+      return;
+    case 'friendCode':
+      navigate('/friends');
+      try {
+        const friend = await gateway.friendCodeRedeem(link.code);
+        showToast(t('friends.added', { name: friend.displayName }));
+        void refreshNotifications();
+      } catch (err) {
+        handleError(err);
+      }
+      return;
+    default:
+      navigate('/');
+  }
+}
+
 export async function loginGuest(): Promise<void> {
   try {
     const s = await gateway.authGuest(app.locale);
@@ -233,6 +283,7 @@ async function persistLanguageToServer(locale: Locale): Promise<void> {
       awayEnd: p.awayEnd,
       blockChat: p.blockChat,
       blockFriendRequests: p.blockFriendRequests,
+      notificationsInAppOnly: p.notificationsInAppOnly,
     });
   } catch {
     // The client locale already changed; the server sync is best-effort.