- Add tools and tool_choice fields to ChatCompletionRequest model
- Update OpenAIProviderHandler to accept and pass tools/tool_choice parameters
- Update handlers to pass tools/tool_choice from request to provider
- Treat tool call errors during streaming as provider failures
- Record failure and re-raise to trigger retry with next model in rotation
- Allows proper tool/function calling support through the proxy
- Resolves 'Tool choice is none, but model called a tool' error by retrying with another model