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.

docs/FUNCTIONAL.md

@@ -22,15 +22,19 @@ Settings also pick the board's bonus-label style (beginner / classic / none). A
 costs nothing when the rack has no legal move. The word-check accepts only the
 variant's alphabet, remembers answers within the session and rate-limits repeats.
 
-### Identity & sessions *(Stage 1 / 6)*
+### Identity & sessions *(Stage 1 / 6 / 9)*
 A player arrives from a platform (Telegram first), via email login, or as an
 ephemeral guest. The gateway validates the credential once and mints a thin
-session token; the backend resolves it to an internal `user_id`. Guests are
-session-only with restricted features (auto-match only; no friends, stats or
-history). While the app is open the client keeps a live stream and receives
-in-app updates in real time — the opponent's move, your turn, chat, nudges and a
-found match; out-of-app push (your turn, nudge) is delivered by the platform
-later (Stage 9).
+session token; the backend resolves it to an internal `user_id`. A **Telegram Mini
+App** launch authenticates from the platform's signed `initData`, themes the UI to
+the Telegram colours, and — on first contact — seeds the new account's interface
+language from the Telegram client. Guests are session-only with restricted features
+(auto-match only; no friends, stats or history). While the app is open the client
+keeps a live stream and receives in-app updates in real time — the opponent's move,
+your turn, chat, nudges and a found match. When the app is **closed**, the chosen
+out-of-app events (your turn, nudge, a found match, an invitation or friend request)
+arrive as a **Telegram notification** instead — unless the player keeps notifications
+in the app only (a profile setting, **on by default**).
 
 ### Accounts, linking & merge *(Stage 1 / 10)*
 First platform contact auto-provisions a durable account. From the profile a
@@ -42,9 +46,9 @@ account (stats summed, games/friends transferred).
 Bottom tab menu: **my games**, **profile**. Auto-match (always 2 players) joins a
 per-variant pool and is paired with the next waiting human; after 10 s with no
 human the robot substitutes (the robot arrives in Stage 5). Friend games (2–4) are
-formed by inviting players from the friend list (deep-link invites arrive with the
-platform integration): the inviter chooses the settings and the game starts once
-every invitee has accepted — any decline cancels it, and an unanswered invitation
+formed by inviting players from the friend list (an invitation, like a friend code,
+is shareable as a Telegram deep link that opens it directly): the inviter chooses the
+settings and the game starts once every invitee has accepted — any decline cancels it, and an unanswered invitation
 expires after seven days.
 
 ### Playing a game *(Stage 3)*