feat(ST-356): add solo Kanban board with DnD and Zustand store
- useSoloStore: initTasks, optimisticMove (returns prev status), rollback, updatePlan
- SoloBoard: DndContext with PointerSensor (distance:5), closestCorners, 3 columns
- SoloColumn: useDroppable per status, MD3 status-color headers, task count, empty state
- SoloTaskCard + SoloTaskCardOverlay: useDraggable (disabled for demo), priority left-border
- onDragEnd: optimisticMove → updateTaskStatusAction → rollback + toast on error
- REVIEW tasks mapped to IN_PROGRESS column
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Madhura68
e1903bc16c