feat: enhance export and import workflows with improved error handling and notifications

templates/base.html

@@ -24,6 +24,7 @@
   <script src="/static/js/projects.js" defer></script>
   <script src="/static/js/exports.js" defer></script>
   <script src="/static/js/imports.js" defer></script>
+  <script src="/static/js/notifications.js" defer></script>
     <script src="/static/js/theme.js"></script>
   </body>
 </html>

templates/exports/modal.html

@@ -45,6 +45,7 @@
           </button>
           <button type="submit" class="btn btn-primary">Download</button>
         </div>
+        <p class="form-error hidden" data-export-error></p>
       </form>
     </div>
   </div>