Fix task and shift self-assignment features

frontend/src/hooks/useShifts.ts

@@ -16,6 +16,7 @@ export interface ShiftListItemDto {
   endTime: string;
   capacity: number;
   currentSignups: number;
+  isSignedUp: boolean;
 }
 
 export interface ShiftDetailDto {
@@ -31,6 +32,7 @@ export interface ShiftDetailDto {
   createdById: string;
   createdAt: string;
   updatedAt: string;
+  isSignedUp: boolean;
 }
 
 export interface ShiftSignupDto {

frontend/src/hooks/useTasks.ts

@@ -11,10 +11,9 @@ export interface TaskListDto {
 
 export interface TaskListItemDto {
   id: string;
-  title: string;
-  status: string;
   assigneeId: string | null;
   createdAt: string;
+  isAssignedToMe: boolean;
 }
 
 export interface TaskDetailDto {
@@ -28,6 +27,7 @@ export interface TaskDetailDto {
   dueDate: string | null;
   createdAt: string;
   updatedAt: string;
+  isAssignedToMe: boolean;
 }
 
 export interface CreateTaskRequest {
@@ -120,3 +120,41 @@ export function useUpdateTask() {
     },
   });
 }
+
+export function useAssignTask() {
+  const queryClient = useQueryClient();
+  const { activeClubId } = useTenant();
+  
+  return useMutation({
+    mutationFn: async (id: string) => {
+      const res = await apiClient(`/api/tasks/${id}/assign`, {
+        method: 'POST',
+      });
+      if (!res.ok) throw new Error('Failed to assign task');
+      return res;
+    },
+    onSuccess: (_, id) => {
+      queryClient.invalidateQueries({ queryKey: ['tasks', activeClubId] });
+      queryClient.invalidateQueries({ queryKey: ['tasks', activeClubId, id] });
+    },
+  });
+}
+
+export function useUnassignTask() {
+  const queryClient = useQueryClient();
+  const { activeClubId } = useTenant();
+  
+  return useMutation({
+    mutationFn: async (id: string) => {
+      const res = await apiClient(`/api/tasks/${id}/assign`, {
+        method: 'DELETE',
+      });
+      if (!res.ok) throw new Error('Failed to unassign task');
+      return res;
+    },
+    onSuccess: (_, id) => {
+      queryClient.invalidateQueries({ queryKey: ['tasks', activeClubId] });
+      queryClient.invalidateQueries({ queryKey: ['tasks', activeClubId, id] });
+    },
+  });
+}