feat: enhance task creation and editing with success/error toasts

- Added success and error toast notifications for task creation in CreateTaskDialog.
- Implemented success and error toast notifications for task updates in EditTaskDialog.
- Integrated custom toast notifications in MentorProjectCard for project archiving.
- Removed unused mock data files related to projects, interns, deadlines, and certificates.
- Updated useProjectTasks hook to accept projectId as a number instead of a string.
- Improved error handling in useSubmission hook methods to throw errors instead of returning null.

src/Pages/utils/showToast.tsx

@@ -1,6 +1,6 @@
 // utils/toast.tsx
 import toast, { type Toast } from 'react-hot-toast';
-import { FiXCircle, FiX } from 'react-icons/fi';
+import { FiX } from 'react-icons/fi';
 import { FaCheck } from "react-icons/fa";
 import { IoAlertOutline } from "react-icons/io5";