Legacy Lists button at one board view to restore missing lists/cards.

Thanks to xet7 !

Fixes #5952

client/components/boards/boardHeader.jade

@@ -130,6 +130,11 @@ template(name="boardHeaderBar")
           a.board-header-btn-close.js-multiselection-reset(title="{{_ 'filter-clear'}}")
             | ❌
 
+      if currentUser.isBoardAdmin
+        a.board-header-btn.js-restore-legacy-lists(title="{{_ 'restore-legacy-lists'}}")
+          | 🔄
+          | {{_ 'legacy-lists'}}
+
       .separator
       a.board-header-btn.js-toggle-sidebar(title="{{_ 'sidebar-open'}} {{_ 'or'}} {{_ 'sidebar-close'}}")
         | ☰

client/components/boards/boardHeader.js

@@ -152,9 +152,32 @@ BlazeComponent.extendComponent({
         'click .js-log-in'() {
           FlowRouter.go('atSignIn');
         },
+        'click .js-restore-legacy-lists'() {
+          this.restoreLegacyLists();
+        },
       },
     ];
   },
+
+  restoreLegacyLists() {
+    // Show confirmation dialog
+    if (confirm('Are you sure you want to restore legacy lists to their original shared state? This will make them appear in all swimlanes.')) {
+      // Call cron method to restore legacy lists
+      Meteor.call('cron.triggerRestoreLegacyLists', (error, result) => {
+        if (error) {
+          console.error('Error restoring legacy lists:', error);
+          alert(`Error: ${error.message}`);
+        } else {
+          console.log('Successfully triggered restore legacy lists migration:', result);
+          alert(`Migration triggered successfully. Job ID: ${result.jobId}`);
+          // Refresh the board to show the restored lists
+          setTimeout(() => {
+            window.location.reload();
+          }, 2000);
+        }
+      });
+    }
+  },
 }).register('boardHeaderBar');
 
 Template.boardHeaderBar.helpers({