Add three state management components:
- LatencyBlockStateManager: tracks providers blocked due to
high latency with configurable block duration and scope
- LatencyTriggerCounter: counts consecutive latency threshold
breaches before triggering provider blocking
- RetryAfterStateManager: honors Retry-After headers with
per-provider/model/endpoint blocking scope
Signed-off-by: Troy Mitchell <i@troy-y.org>
Implement RetryErrorResponseBuilder that constructs structured
JSON error responses when all retry attempts are exhausted,
including per-attempt error details and provider information.
Signed-off-by: Troy Mitchell <i@troy-y.org>
Add the retry module with core type definitions including:
- RequestContext, RequestSignature for request deduplication
- RetryExhaustedError, AllProvidersExhaustedError for error handling
- AttemptError, AttemptErrorType for attempt tracking
- ValidationError, ValidationWarning for config validation
- Helper functions for provider extraction and hashing
Wire up pub mod retry in lib.rs.
Signed-off-by: Troy Mitchell <i@troy-y.org>
