Silent failures in Chat UI (Lack of error toasts/timeouts)

[A561988]

Testing the chat interface—there seems to be zero feedback when an RPC call fails. If the gateway rejects a request, the UI just shows an eternal loading spinner.
Checked DevTools and I see the WebSocket returning ok: false, but there's no toast notification or timeout surfacing this to the user. Without proper error recovery, it's impossible to know if the model is stalled or if it's a permission/network issue.

[VGIL77]

Confirmed — this is a real UX gap. The WebSocket RPC layer returns { ok: false, error: {...} } on failures but the Control UI doesn't surface those as toasts, and there's no client-side timeout guard so a hung request yields an infinite spinner.

This likely ties into #4 as well — when the gateway strips scopes silently, the UI sees an ok: false but has nowhere to route it, so the user just waits forever.

What this probably needs:

1. A generic RPC error handler in the Control UI's WebSocket client (desktop/renderer/) that shows a toast on any ok: false response
2. A configurable per-request timeout (say 30s default) that rejects and surfaces a "Request timed out" toast
3. Structured error types so specific errors (auth/permission/rate-limit) get targeted messaging instead of a generic toast

Leaving open. PR welcome.