fix(web): add dismiss button to thread error banner (#588)

The thread error banner had no way to be dismissed. Users hitting
unrecoverable errors (e.g. missing gh CLI during PR creation) were
stuck with a persistent error banner and no way to clear it.

Add a dismiss (X) button to ThreadErrorBanner using the existing
AlertAction component, wired to clear the thread error via
setThreadError(id, null).

Closes #496
59e2944fb70x1f99d committed on 3/9/2026, 1:24:56 AM· committed by GitHubparent1794278
1 file changedLine totals unavailable