- Update ToolRegistry.ExecuteWithContext to accept asyncCallback parameter
- Check if tool implements AsyncTool and set callback if provided
- Define asyncCallback in AgentLoop.runLLMIteration
- Callback uses bus.PublishOutbound to send async results to user
- Update Execute method to pass nil for backward compatibility
- Add debug logging for async callback injection
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>