feat: realtime WebSocket layer for live events and streaming logs

- Backend: ConnectionManager, Redis-backed bus with in-process fallback,
  channel authorization, and typed emit helpers wired into workers
  (ai_runtime, sandbox_gateway), workforce/sandbox/billing/audit/error services.
- Frontend: single shared WS client with backoff + heartbeat, RealtimeProvider,
  useLiveChannel/useLiveEvent hooks, live indicators on task detail, manager
  chat, dashboard, traces, sandbox terminal, admin errors, and billing.
- Contracts: WsEvent/WsServerFrame/WsClientFrame types mirroring the port.

All 255 backend tests pass; web typecheck and build pass.

apps/api/app/core/config.py

@@ -53,6 +53,15 @@ class Settings(BaseSettings):
     database_url: str = "sqlite+aiosqlite:///./agy_web.db"
     redis_url: str = "redis://localhost:6379/0"
 
+    # --- realtime push -------------------------------------------------------
+    #: How live events travel between processes. ``auto`` mirrors published
+    #: events onto Redis pub/sub so the standalone workers' pushes reach the
+    #: API process's browser sockets; if no broker is reachable the bus falls
+    #: back to in-process fan-out and every API-driven feed stays live.
+    #: ``local`` pins the bus to in-process delivery (tests, single-process
+    #: deployments without a broker).
+    realtime_transport: str = "auto"
+
     # --- security ------------------------------------------------------------
     jwt_secret: str = "change-me"
     jwt_algorithm: str = "HS256"