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/OnboardMeetingMembersView.vue

@@ -39,7 +39,7 @@
 
 <script lang="ts">
 import { Component, Vue } from "vue-facing-decorator";
-import { RouteLocation } from "vue-router";
+import { RouteLocationNormalizedLoaded, Router } from "vue-router";
 
 import QuickNav from "../components/QuickNav.vue";
 import TopMessage from "../components/TopMessage.vue";
@@ -69,17 +69,17 @@ export default class OnboardMeetingMembersView extends Vue {
   firstName = "";
   isRegistered = false;
   isLoading = true;
+  $route!: RouteLocationNormalizedLoaded;
+  $router!: Router;
 
-  $refs!: {
-    userNameDialog: InstanceType<typeof UserNameDialog>;
-  };
+  userNameDialog!: InstanceType<typeof UserNameDialog>;
 
   get groupId(): string {
-    return (this.$route as RouteLocation).params.groupId as string;
+    return (this.$route.params.groupId as string) || "";
   }
 
   get password(): string {
-    return (this.$route as RouteLocation).query.password as string;
+    return (this.$route.query.password as string) || "";
   }
 
   async created() {