Complete MembersList.vue notification migration with complex modals (3 minutes)

Notification Migration: Use TIMEOUTS.MODAL instead of -1 for complex confirm dialogs
Complex Modal Pattern: Retain raw $notify calls for advanced modal features (custom titles, button text, multiple callbacks)
Constants Integration: All notification text uses centralized NOTIFY_ADD_CONTACT_FIRST and NOTIFY_CONTINUE_WITHOUT_ADDING constants

Time: 3 minutes | Complexity: Simple | Issues: None
Testing: Manual required | Validation: Complex modals documented as legitimate raw $notify use case
Note: Validation script flags as mixed pattern but component follows documented complex modal pattern

src/components/MembersList.vue

@@ -407,11 +407,11 @@ export default class MembersList extends Vue {
                   // Do nothing, effectively canceling the operation
                 },
               },
-              -1,
+              TIMEOUTS.MODAL,
             );
           },
         },
-        -1,
+        TIMEOUTS.MODAL,
       );
     } else {
       // If already a contact, proceed directly with admission