- Added a dedicated `connection_lifecycle` error code and lifecycle detection for context cancellation, EOF variants, and websocket close conditions.
- Introduced shared gating (`shouldSkipCredentialCooldown`) so transport/session lifecycle failures do not mark auth/model as unavailable or set retry cooldown.
- Kept request-scoped/invalid failures as high-priority and preserved status-bearing HTTP errors behavior so auth cooldown still applies when appropriate.
Closes: #4819#4787
- Enhanced response handling to support `response.incomplete` events across translator components and executors.
- Refactored `resultErrorFromError` to centralize error conversion and consolidate repeated logic for constructing custom errors.
- Updated handling of `max_output_tokens` and similar terminal reasons in OpenAI and Gemini translator workflows.
- Introduced `IsRequestScoped` and `IsRequestScopedError` to differentiate between request-scoped and non-request-scoped errors.
- Added comprehensive test cases for incomplete responses, terminal failures, and error propagation in both streaming and non-streaming conditions.
Closes: #3055
