Wrap waitForCompactionRetry() in try/catch to capture AbortError
that was escaping and bypassing the model fallback mechanism.
When a timeout fires, session.abort() causes both session.prompt()
and waitForCompactionRetry() to throw AbortError. Previously only
the prompt error was captured, allowing the compaction error to
escape to model-fallback.ts where it was immediately re-thrown
(line 199: isAbortError check), bypassing fallback model attempts.
Fixes#313
cd4e2023ab