feat: enhance service discovery and proxy management

frontend/src/App.vue

@@ -2,6 +2,7 @@
 import { onMounted, provide } from "vue";
 
 import AppHeader from "./components/AppHeader.vue";
+import AppToast from "./components/AppToast.vue";
 import LoginView from "./components/LoginView.vue";
 import ProxyList from "./components/ProxyList.vue";
 import ProxyWorkbench from "./components/ProxyWorkbench.vue";
@@ -24,15 +25,17 @@ onMounted(() => {
     v-model:username="plane.username"
     v-model:password="plane.password"
     :loading="plane.loading"
-    :error="plane.error"
+    :error="plane.authMessage || plane.error"
     @submit="plane.signIn"
   />
 
   <main v-else class="app-shell">
+    <AppToast v-if="plane.notice" :message="plane.notice" />
+
     <AppHeader
       :loading="plane.loading"
       @refresh="plane.refreshAll"
-      @create="plane.newProxy"
+      @create="plane.openCreateWizard()"
       @logout="plane.signOut"
     />