fix: align frontend status types with API string enum serialization

ASP.NET serializes C# enums as strings by default ("Pending", "Active"),
but frontend types used numeric values (0, 1). Changed WorkTaskStatus and
NoteType to string values matching API output.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

TaskTracker.Web/src/components/KanbanBoard.tsx

@@ -70,11 +70,11 @@ export default function KanbanBoard({ tasks, isLoading, onTaskClick }: KanbanBoa
       if (!task) return
 
       // Determine target status from the droppable column ID
-      let targetStatus: number | null = null
+      let targetStatus: string | null = null
       const overId = String(over.id)
 
       if (overId.startsWith('column-')) {
-        targetStatus = Number(overId.replace('column-', ''))
+        targetStatus = overId.replace('column-', '')
       } else {
         // Dropped over another card - find which column it belongs to
         const overTaskId = Number(over.id)
@@ -136,7 +136,7 @@ export default function KanbanBoard({ tasks, isLoading, onTaskClick }: KanbanBoa
             color={col.color}
             tasks={col.tasks}
             onTaskClick={onTaskClick}
-            onAddTask={col.status === 0 ? () => {} : undefined}
+            onAddTask={col.status === WorkTaskStatus.Pending ? () => {} : undefined}
           />
         ))}
       </div>