Make provider auto-retry signal detection respect timeout_seconds setting:
- When timeout_seconds=0, disable quota-based fallback escalation
- Only treat auto-retry signals as errors when timeout is enabled
- Add test to verify behavior when timeout_seconds is disabled
- Update documentation to explain timeout_seconds=0 behavior
This allows users to disable timeout-based fallbacks while keeping
error-based fallback functionality intact.
Youngbin Kim
68f5d982fc