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.

gateway/internal/transcode/transcode_social_test.go

@@ -2,6 +2,7 @@ package transcode_test
 
 import (
 	"context"
+	"encoding/json"
 	"net/http"
 	"testing"
 
@@ -202,11 +203,15 @@ func TestGcgRoundTrip(t *testing.T) {
 }
 
 func TestProfileUpdateRoundTripAway(t *testing.T) {
+	var gotBody map[string]any
 	backend, cleanup := fakeBackend(t, func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != http.MethodPut || r.URL.Path != "/api/v1/user/profile" {
 			t.Errorf("unexpected %s %q", r.Method, r.URL.Path)
 		}
-		_, _ = w.Write([]byte(`{"user_id":"u-1","display_name":"Kaya","preferred_language":"ru","time_zone":"Europe/Moscow","away_start":"00:00","away_end":"07:30"}`))
+		_ = json.NewDecoder(r.Body).Decode(&gotBody)
+		// Respond with notifications_in_app_only=false to exercise the encode path
+		// carrying a non-default value back to the client.
+		_, _ = w.Write([]byte(`{"user_id":"u-1","display_name":"Kaya","preferred_language":"ru","time_zone":"Europe/Moscow","away_start":"00:00","away_end":"07:30","notifications_in_app_only":false}`))
 	})
 	defer cleanup()
 
@@ -225,6 +230,7 @@ func TestProfileUpdateRoundTripAway(t *testing.T) {
 	fb.UpdateProfileRequestAddTimeZone(b, tz)
 	fb.UpdateProfileRequestAddAwayStart(b, as)
 	fb.UpdateProfileRequestAddAwayEnd(b, ae)
+	fb.UpdateProfileRequestAddNotificationsInAppOnly(b, true)
 	b.Finish(fb.UpdateProfileRequestEnd(b))
 
 	payload, err := op.Handler(context.Background(), transcode.Request{UserID: "u-1", Payload: b.FinishedBytes()})
@@ -235,4 +241,12 @@ func TestProfileUpdateRoundTripAway(t *testing.T) {
 	if string(p.AwayStart()) != "00:00" || string(p.AwayEnd()) != "07:30" || string(p.PreferredLanguage()) != "ru" {
 		t.Fatalf("profile away round-trip wrong: start=%q end=%q lang=%q", p.AwayStart(), p.AwayEnd(), p.PreferredLanguage())
 	}
+	// The request's in-app-only flag (true) must reach the backend, and the backend's
+	// value (false) must come back in the encoded Profile.
+	if v, ok := gotBody["notifications_in_app_only"].(bool); !ok || v != true {
+		t.Errorf("forwarded notifications_in_app_only = %v (ok=%v), want true", gotBody["notifications_in_app_only"], ok)
+	}
+	if p.NotificationsInAppOnly() {
+		t.Error("response notifications_in_app_only = true, want false")
+	}
 }