- Add response.function_call_arguments.delta handler for tool call parameters
- Rewrite normalizeGitHubCopilotResponsesInput to produce structured input
array (message/function_call/function_call_output) instead of flattened
text, fixing infinite loop in multi-turn tool-use conversations
- Skip flattenAssistantContent for messages containing tool_use blocks,
preventing function_call items from being destroyed
- Add reasoning/thinking stream & non-stream support
- Fix stop_reason mapping (max_tokens/stop) and cached token reporting
- Update test to match new array-based input format
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>