fix(ui): DNS apply no longer blanks the page + WiFi/DNS modals cover the whole app

Applying DNS assigned the RPC response's fields into networkData without
guarding the shape; the demo mock answered {success:true} with no
servers array, dnsServers became undefined, and the dnsDisplayLabel
computed crashed the whole page render on .length. Guard the assignment,
teach the mock to round-trip DNS state per session, and Teleport the
WiFi + DNS modals to body so they overlay the full app instead of just
the right panel (position:fixed is containing-block-relative inside the
dashboard).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/views/server/ServerModals.vue

@@ -94,6 +94,7 @@
   </Teleport>
 
   <!-- WiFi Scan Modal -->
+  <Teleport to="body">
   <div v-if="showWifiModal" class="fixed inset-0 bg-black/60 backdrop-blur-md z-50 flex items-center justify-center p-4" @click.self="$emit('closeWifi')">
     <div class="glass-card p-6 w-full max-w-md">
       <div class="flex items-center justify-between mb-4">
@@ -161,8 +162,10 @@
       </div>
     </div>
   </div>
+  </Teleport>
 
   <!-- DNS Configuration Modal -->
+  <Teleport to="body">
   <div v-if="showDnsModal" class="fixed inset-0 bg-black/60 backdrop-blur-md z-50 flex items-center justify-center p-4" @click.self="$emit('closeDns')">
     <div class="glass-card p-6 w-full max-w-md">
       <div class="flex items-center justify-between mb-4">
@@ -223,6 +226,7 @@
       </div>
     </div>
   </div>
+  </Teleport>
 </template>
 
 <script setup lang="ts">