- Handle empty error messages in subtask-breakdown session by falling back to 'Unknown error'
- Fix backend SSE routes to coerce error data to string and handle missing message
- Improve frontend connectSubtaskStream to validate parsed error data before displaying
- Add tests for error display in SubtaskBreakdownModal component
- Change default task prefix from KB to FN across all packages
- Rename branch naming pattern from kb/{id} to fusion/{id}
- Update all test assertions and fixtures to use new prefixes
- Add changeset for the breaking change
- Resolve merge conflicts in TaskCard.test.tsx touch gesture tests
- Add backend subtask breakdown session management and API endpoints
- Create SubtaskBreakdownModal component for generating AI-suggested subtasks
- Integrate subtask breakdown into QuickEntryBox and NewTaskModal flows
- Add frontend API client functions for breakdown sessions and subtask creation
- Add tests for SubtaskBreakdownModal and backend routes
- Create changeset documenting the subtask breakdown feature
