Backend:
- Add self-referencing parent_task_id FK on project_tasks with CASCADE delete
- Add Alembic migration 002 for parent_task_id column + index
- Update schemas with parent_task_id in create, nested subtasks in response
- Chain selectinload for subtasks on all project queries
- Validate parent must be top-level task (single nesting level only)
Frontend:
- Add parent_task_id and subtasks[] to ProjectTask type
- ProjectDetail: expand/collapse chevrons, subtask progress bars, inline
subtask rendering with accent left border, add/edit/delete subtask buttons
- TaskForm: accept parentTaskId prop, include in create payload, context-aware
dialog title (New Task vs New Subtask)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
