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/components/UserNameDialog.vue

@@ -37,7 +37,6 @@
 <script lang="ts">
 import { Vue, Component, Prop } from "vue-facing-decorator";
 
-
 import { MASTER_SETTINGS_KEY } from "../db/tables/settings";
 import { PlatformServiceFactory } from "@/services/PlatformServiceFactory";
 import { PlatformServiceMixin } from "@/utils/PlatformServiceMixin";