## Why
An explicit denial from a workspace inference hook should stop the request, including retries and compaction model fallback.
## What changed
Recognize `inference_hook_denied` provider errors and preserve the provider's message, with a fallback when none is supplied. Expose the distinct `inferenceHookDenied` error through the app-server protocol and generated schemas and SDK types. Treat the denial as non-retryable during turns, compaction, and guardian review.
## Testing
Add coverage for terminal denials over HTTP, SSE, and WebSocket, error serialization and persistence in `thread/read`, and compaction failures that preserve token usage and history without retrying or falling back to another model.
GitOrigin-RevId: 2ebd480f01e52f4e6bd3db8a0f92d5814d18ccb1