* fix(ai-validation): comprehensive fixes for AI response validation issues
- Fix update command validation when AI omits subtasks/status/dependencies
- Fix add-task command when AI returns non-string details field
- Fix update-task command when AI subtasks miss required fields
- Add preprocessing to ensure proper field types before validation
- Prevent split() errors on non-string fields
- Set proper defaults for missing required fields
* chore: run format
* chore: implement coderabbit suggestions