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/web/src/app/layout.tsx

@@ -1,5 +1,6 @@
 import type { Metadata } from "next";
 import "./globals.css";
+import { RealtimeProvider } from "@/lib/realtime";
 import { SessionProvider } from "@/lib/session";
 
 export const metadata: Metadata = {
@@ -11,7 +12,10 @@ export default function RootLayout({ children }: { children: React.ReactNode })
   return (
     <html lang="fa" dir="rtl" className="dark">
       <body>
-        <SessionProvider>{children}</SessionProvider>
+        <SessionProvider>
+          {/* One socket for the whole app: every live feed rides on it. */}
+          <RealtimeProvider>{children}</RealtimeProvider>
+        </SessionProvider>
       </body>
     </html>
   );