Phase 7: Bot/extension system

Bot accounts (User rows with is_bot=True), scoped API tokens (read:messages,
write:messages, manage:rooms) authenticated via Authorization: Bearer on both
REST and the WS handshake, live bot WebSocket access on the same /ws/chat
endpoint humans use, message editing (WS "edit" envelope -> message_update
broadcast, fans out cross-instance for free via the existing broadcaster),
incoming webhooks (room-scoped, no auth beyond the URL token), and outgoing
webhooks/event subscriptions (HMAC-SHA256 signed, backgrounded delivery,
creation-time SSRF validation against private/loopback/link-local targets).

Token auth is additive, not a parallel system: a bearer-token-authenticated
bot goes through the exact same room-membership/role checks a session-
authenticated human does everywhere; only read:messages/write:messages are
separately scope-gated (the two message endpoints). manage:rooms scope
enforcement, full per-delivery SSRF re-validation, and bot API rate limiting
were explicitly scoped out (confirmed with the repo owner) as disproportionate
to this phase -- documented as known gaps in backend/README.md rather than
silently skipped.

Admin portal gains a Bots tab (create bots, issue/revoke scoped tokens,
cross-room webhook visibility); RoomInfoPanel gains room-scoped webhook/
subscription management, mirroring how invites already work there. The chat
UI also gets a minimal "edit your own message" affordance -- not asked for
by the issue, but the only practical way to exercise the edit pipeline by
hand instead of only via a scripted bot client.

Along the way: fixed a real bug caught while writing the incoming-webhook
test -- offline-push notification relied on the sender being "connected" to
exclude themselves, true for WS-originated messages but not for the new
webhook path, which has no WS connection for the attributed sender at all.
Now explicitly excluded. Also discovered the REST-only test fixture never
triggered ASGI lifespan, so app.state.broadcaster/presence didn't exist for
it; moved their construction out of the lifespan into create_app() itself
(Redis client construction is synchronous/lazy) so both the WS and
REST-only paths always have them.

New tests/test_bots.py, test_message_edit.py, test_webhooks.py (full suite
now 78/78, stable across repeated runs) plus a scripted end-to-end smoke
test (bot WS join/post/edit, incoming webhook, SSRF rejection, outgoing
delivery) and a full browser walkthrough of the new admin/room UI.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/app/main.py

@@ -8,7 +8,7 @@ from redis.asyncio import Redis
 from starlette.middleware.sessions import SessionMiddleware
 
 from app.config import settings
-from app.routers import admin, auth, health, invites, push, rooms
+from app.routers import admin, auth, bots, health, invites, push, rooms, webhooks
 from app.ws.broadcaster import RoomBroadcaster
 from app.ws.chat import router as ws_router
 from app.ws.connection_manager import ConnectionManager
@@ -17,18 +17,22 @@ from app.ws.presence import Presence
 
 @asynccontextmanager
 async def lifespan(app: FastAPI) -> AsyncIterator[None]:
-    redis = Redis.from_url(settings.redis_url, decode_responses=True)
-    app.state.presence = Presence(redis)
-    broadcaster = RoomBroadcaster(redis, app.state.connection_manager)
-    app.state.broadcaster = broadcaster
-    listener_task = asyncio.create_task(broadcaster.listen())
+    # redis/presence/broadcaster are constructed in create_app(), not here --
+    # Redis.from_url() is synchronous/lazy (no connection opens until the
+    # first command), so app.state.presence/broadcaster are always present
+    # even for callers that never trigger the ASGI lifespan (e.g. httpx's
+    # ASGITransport, used by the plain REST test fixtures -- only
+    # TestClient's websocket_connect-based tests actually run lifespan).
+    # The background listener task genuinely needs a running event loop
+    # though, so that part stays here.
+    listener_task = asyncio.create_task(app.state.broadcaster.listen())
 
     yield
 
     listener_task.cancel()
     with contextlib.suppress(asyncio.CancelledError):
         await listener_task
-    await redis.aclose()
+    await app.state.redis.aclose()
 
 
 def create_app() -> FastAPI:
@@ -43,6 +47,9 @@ def create_app() -> FastAPI:
     )
 
     app.state.connection_manager = ConnectionManager()
+    app.state.redis = Redis.from_url(settings.redis_url, decode_responses=True)
+    app.state.presence = Presence(app.state.redis)
+    app.state.broadcaster = RoomBroadcaster(app.state.redis, app.state.connection_manager)
 
     app.include_router(health.router)
     app.include_router(auth.router)
@@ -50,6 +57,8 @@ def create_app() -> FastAPI:
     app.include_router(invites.router)
     app.include_router(push.router)
     app.include_router(admin.router)
+    app.include_router(bots.router)
+    app.include_router(webhooks.router)
     app.include_router(ws_router)
 
     return app