Track when executor calls cross an upstream transport boundary and use that
signal to keep model/provider errors from being replaced by later local
preparation, selection, or internal failures.
Mark HTTP, websocket, relay, and usage-tracked transports as upstream
attempts, while avoiding marks for local validation, logging, missing
sessions, and successful websocket handshakes before request send.
Parse relative auth expiry metadata and adjust Antigravity refresh timing.
- Introduced `deferredRequestBodyCapture` for spooling and retaining large error-only request bodies for improved logging.
- Enhanced `RequestLoggingMiddleware` to capture request body based on size and error criteria.
- Implemented decompression and truncation for large request bodies with Zstd encoding.
- Added support for deferred API request logging and context tracking.
- Included extensive test coverage for error-specific body capture and serialization behavior.
- Added APIs to store, retrieve, and clone upstream response headers in context for detailed logging.
- Updated `RecordAPIResponseMetadata`, `RecordAPIWebsocketHandshake`, and related methods to capture response headers.
- Extended `UsageReporter` to include response headers in published usage records.
- Enhanced payload tests to validate response headers' integrity and persistence.
- Refactored `usage.Record` to support optional `ResponseHeaders` field.
