- Add ApprovalState dataclass for approval workflow state
- Add ApprovalHandler class with:
- APPROVAL_PATTERNS for detection (AskUserQuestion, ExitPlanMode, 需要确认, Please confirm)
- detect_approval_request() to find approval requests in output
- create_approval_card() with confirm/reject buttons using CardButton
- handle_callback() to process approval actions
- In-memory pending_approvals cache
- Fix test assertions to use kwargs instead of positional args
All 8 tests pass for approval handling.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>