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.

platform/telegram/Dockerfile

@@ -0,0 +1,22 @@
+# Telegram connector image.
+#
+# The connector imports only the shared scrabble/pkg module, so the build drops the
+# other workspace modules (backend, gateway) and the scrabble-solver replace from a
+# copy of go.work: it needs neither their sources nor the solver sibling checkout.
+# Build from the repository ROOT so go.work, pkg/ and platform/telegram/ are all in
+# the context (see deploy/docker-compose.yml, which sets context: ../../..).
+FROM golang:1.26.3-alpine AS build
+WORKDIR /src
+
+COPY go.work go.work.sum ./
+COPY pkg ./pkg
+COPY platform/telegram ./platform/telegram
+
+# Reduce the workspace to what the connector needs: only pkg + platform/telegram.
+RUN go work edit -dropuse=./backend -dropuse=./gateway -dropreplace=scrabble-solver
+
+RUN CGO_ENABLED=0 GOOS=linux go build -trimpath -o /out/telegram ./platform/telegram/cmd/telegram
+
+FROM gcr.io/distroless/static-debian12:nonroot
+COPY --from=build /out/telegram /usr/local/bin/telegram
+ENTRYPOINT ["/usr/local/bin/telegram"]