Replace hardcoded notification strings with standardized constants

- Replace literal strings with notification constants in ContactsView.vue:
  * "Got an error sending the invite." → NOTIFY_INVITE_ERROR.message
  * "Could not set visibility on the server." → NOTIFY_VISIBILITY_ERROR.message
  * "Unconfirmed Hours" → NOTIFY_UNCONFIRMED_HOURS.title
- Remove unused NOTIFY_REGISTER_PROCESSING import
- Remove unused NOTIFICATION_TIMEOUTS constant in ShareMyContactInfoView.vue
- Fix unused parameter warnings in danger() and warning() methods
- Resolve all notification-related linting errors

src/views/ContactImportView.vue

@@ -348,7 +348,7 @@ export default class ContactImportView extends Vue {
    */
   async created() {
     this.notify = createNotifyHelpers(this.$notify);
-    
+
     await this.initializeSettings();
     await this.processQueryParams();
     await this.processJwtFromPath();