fix: detect quota exhaustion from stream; map to BUDGET_EXCEEDED not FAILED

When claude hits the 5-hour usage limit it exits 1. execOnce was
returning the generic "exit status 1" error, hiding the real cause from
the retry loop and the task state machine.

Fix:
- execOnce now surfaces streamErr when it indicates rate limiting or
  quota exhaustion, so callers see the actual message.
- New isQuotaExhausted() detects "hit your limit" messages — these are
  not retried (retrying a depleted 5h bucket wastes nothing but is
  pointless), and map to BUDGET_EXCEEDED in both execute/executeResume.
- isRateLimitError() remains for transient throttling (429/overloaded),
  which continues to trigger exponential backoff retries.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions