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/UI_DESIGN.md

@@ -5,8 +5,10 @@ Visual and interaction conventions for the `ui` client. Behaviour lives in
 points this doc references) lives in [`ARCHITECTURE.md`](ARCHITECTURE.md). The client
 is **pure HTML5/CSS + Unicode** — no image/font/SVG assets; icons are CSS shapes or
 emoji glyphs. Tokens are CSS custom properties (`ui/src/app.css`), light/dark via
-`prefers-color-scheme` or an explicit Settings choice, and **Telegram-themeParams-ready**
-(the tokens can be overridden at runtime).
+`prefers-color-scheme` or an explicit Settings choice, and **Telegram-themed** (Stage 9):
+on a Telegram Mini App launch — the app is served under `/telegram/` and detects the
+launch by `Telegram.WebApp.initData` — the SDK's `themeParams` override the tokens at
+runtime; opened outside Telegram, the `/telegram/` path redirects to the site root.
 
 ## Layout shell (`components/Screen.svelte`)