When a docling-serve instance crashes or returns 5xx, DoclingServeClient now
retries the request on a different instance (up to max_attempts) and trips a
per-instance circuit breaker so subsequent jobs skip a dead instance until its
cooldown elapses. Reuses the shared CircuitBreaker; adds max_attempts and a
nested circuit_breaker to providers.docling_serve.
Co-Authored-By: bryan davis <bryan@monkeytronics.org>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
