Frontend: Redirect CE admin/cluster/instances stubs to default route

These pages only exist as Plus/Pro/Portal overlays; in editions without
the overlay they now redirect to the user's default route via
$session.getDefaultRoute() instead of rendering a placeholder.

frontend/src/page/admin.vue

@@ -1,17 +1,13 @@
 <template>
-  <p-page-about></p-page-about>
+  <div class="p-page p-page-admin"></div>
 </template>
-
 <script>
-import PPageAbout from "./about/about.vue";
-
+// PPageAdmin is a Community Edition stub: the admin area only exists as a
+// Plus/Pro/Portal overlay, so in CE it redirects to the user's default route.
 export default {
   name: "PPageAdmin",
-  components: { PPageAbout },
-  data() {
-    return {
-      rtl: this.$isRtl,
-    };
+  created() {
+    this.$router.replace({ name: this.$session.getDefaultRoute() });
   },
   mounted() {
     this.$view.enter(this);

frontend/src/page/cluster.vue

@@ -1,17 +1,13 @@
 <template>
-  <p-page-about></p-page-about>
+  <div class="p-page p-page-cluster"></div>
 </template>
-
 <script>
-import PPageAbout from "./about/about.vue";
-
+// PPageCluster is a Community Edition stub: the cluster UI only exists as a
+// Portal overlay, so in CE/Plus/Pro it redirects to the user's default route.
 export default {
   name: "PPageCluster",
-  components: { PPageAbout },
-  data() {
-    return {
-      rtl: this.$isRtl,
-    };
+  created() {
+    this.$router.replace({ name: this.$session.getDefaultRoute() });
   },
   mounted() {
     this.$view.enter(this);

frontend/src/page/instances.vue

@@ -1,15 +1,13 @@
 <template>
   <div class="p-page p-page-instances"></div>
 </template>
-
 <script>
-// PPageInstances is a Community Edition stub for the Portal instance selector,
-// which only exists as an overlay. CE has no cluster instances, so this base
-// redirects to the default route instead of rendering a blank page.
+// PPageInstances is a Community Edition stub: the instance selector only exists
+// as a Portal overlay, so in CE/Plus/Pro it redirects to the user's default route.
 export default {
   name: "PPageInstances",
   created() {
-    this.$router.replace({ name: "home" });
+    this.$router.replace({ name: this.$session.getDefaultRoute() });
   },
   mounted() {
     this.$view.enter(this);