fix(api): harden notification task status updates

packages/api/src/router/notification-task-procedure-support.ts

@@ -131,6 +131,7 @@ export async function updateNotificationTaskStatus(
     where: {
       id: input.id,
       OR: [{ userId }, { assigneeId: userId }],
+      category: { in: ["TASK", "APPROVAL"] },
     },
   });
 
@@ -146,7 +147,9 @@ export async function updateNotificationTaskStatus(
     where: { id: input.id },
     data: {
       taskStatus: input.status,
-      ...(isCompleting ? { completedAt: new Date(), completedBy: userId } : {}),
+      ...(isCompleting
+        ? { completedAt: new Date(), completedBy: userId }
+        : { completedAt: null, completedBy: null }),
     },
   });