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/App.tsx

@@ -135,7 +135,7 @@ function App() {
               <Route path="projects/:slug/:taskSlug/:nameIntern" element={<ViewInternSubmission />} />
               <Route path="faq" element={<FAQPage />} />
               <Route path="notifications" element={<NotificationList />} />
-              <Route path="settings" element={<MentorSettingsPage />} />
+              <Route path="settings" element={<SettingsContent />} />
             </Route>
           </Route>