US-104: Kanban board UI shell
- Loading skeleton while fetching
- 4 columns with task counts
- Empty state with drop zone highlight
US-105: Task card component
- Type icons and color-coded borders
- Priority badges
- Project tags
- Tooltip on hover for full title
- Click opens detail panel
US-106: Create task dialog
- All fields working
- Validation and defaults
US-107: Task detail panel (new)
- Slide-out sheet from right
- Inline editing for all fields
- Debounced auto-save (500ms)
- Delete with confirmation dialog
- Escape key to close
- Metadata display (created/updated)
US-108: Drag and drop
- Visual feedback (ring highlight, ghost card)
- Status update on drop
- Persists to file via API
Added shadcn components: sheet, skeleton, tooltip, alert-dialog
