refactor: improve router type safety and usage

- Add explicit Router type imports across views
- Replace $router type casting with proper typing
- Use $router.back() instead of $router.go(-1) for consistency
- Add proper route and router typings to components
- Clean up router navigation methods
- Fix router push/back method calls

This commit improves type safety and consistency in router usage across
the application's view components.

src/views/HelpNotificationsView.vue

@@ -313,11 +313,12 @@ import { DIRECT_PUSH_TITLE, sendTestThroughPushServer } from "../libs/util";
 import PushNotificationPermission from "../components/PushNotificationPermission.vue";
 import { db } from "../db/index";
 import { MASTER_SETTINGS_KEY } from "../db/tables/settings";
+import { Router } from "vue-router";
 
 @Component({ components: { PushNotificationPermission, QuickNav } })
 export default class HelpNotificationsView extends Vue {
   $notify!: (notification: NotificationIface, timeout?: number) => void;
-
+  $router!: Router;
   subscriptionJSON?: PushSubscriptionJSON;
 
   async mounted() {