1. Add README, LICENSE (MIT), .gitignore, Makefile, CHANGELOG
2. Add Version constant and User-Agent header to all requests
3. Rename SetStream to EnableStream (narrower API surface)
4. Fix FinishReason in CompletionStreamChoice to use typed *FinishReason
5. Type conversation entry Content as chat.Content instead of json.RawMessage
6. Graceful unknown type handling — UnknownEntry, UnknownEvent,
UnknownChunk, UnknownMessage, UnknownAgentTool all return data
instead of erroring on unrecognized discriminator values
7. Type agent tools with AgentTool sealed interface + UnmarshalAgentTool
8. Add pagination params to ListConversations and ListLibraries
9. Move openapi.yaml to docs/openapi.yaml
Add retry logic to all HTTP methods:
- doRetry() core loop with configurable max retries
- Exponential backoff with 0.5-1.5x jitter
- Retry-After header support (seconds and HTTP-date)
- Retry on 429 and 5xx; no retry on 4xx client errors
- Context cancellation respected during retry delays
- Multipart uploads also retry via doRetry()
- 9 new tests: 429/500 recovery, exhaustion, no-retry-on-400, backoff math
