- Added `isError` property to `EmbeddedPiRunResult` and reply items to indicate error states.
- Updated error handling in `runReplyAgent` to provide more informative messages for specific socket connection errors.
Detect the Gemini API error 'function call turn comes immediately after
a user turn or after a function response turn' which indicates corrupted
session history.
When detected:
- Delete the corrupted transcript file
- Remove the session entry from the store
- Return a user-friendly message asking them to retry
This prevents the error loop where every subsequent message fails with
the same error until manual intervention.
Fixes#296