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/OnboardMeetingListView.vue

@@ -120,6 +120,7 @@ export default class OnboardMeetingListView extends Vue {
     },
     timeout?: number,
   ) => void;
+  $router!: Router;
 
   activeDid = "";
   apiServer = "";
@@ -257,7 +258,7 @@ export default class OnboardMeetingListView extends Vue {
 
       if (postResult.data && postResult.data.success) {
         // Navigate to members view with password and groupId
-        (this.$router as Router).push({
+        this.$router.push({
           name: "onboard-meeting-members",
           params: {
             groupId: this.selectedMeeting.groupId.toString(),