Add user-owned IM channel connections

backend/app/gateway/app.py

@@ -15,6 +15,7 @@ from app.gateway.routers import (
     artifacts,
     assistants_compat,
     auth,
+    channel_connections,
     channels,
     feedback,
     mcp,
@@ -376,6 +377,9 @@ This gateway provides runtime endpoints for agent runs plus custom endpoints for
     # Suggestions API is mounted at /api/threads/{thread_id}/suggestions
     app.include_router(suggestions.router)
 
+    # User-facing IM channel connection API is mounted at /api/channels
+    app.include_router(channel_connections.router)
+
     # Channels API is mounted at /api/channels
     app.include_router(channels.router)