feat(xray/dns): align DNS settings with Xray docs + UI polish

- DNS server modal: rename expectIPs -> expectedIPs (per docs); add
  per-server tag, clientIP, serveStale, serveExpiredTTL, timeoutMs;
  flip skipFallback default to false; hydration still accepts legacy
  expectIPs for back-compat.
- DNS tab: add hosts editor (domain -> IP/array), serveStale +
  serveExpiredTTL controls, "Use Preset" button bringing back the
  legacy preset gallery (Google / Cloudflare / AdGuard + Family
  variants — fixed AdGuard Family IPs that were wrong in legacy),
  and a "Delete All" button to wipe the server list at once.
- i18n: add 15 new dns.* keys across all 13 locales.
- Frontend-wide formatter pass on Vue components (whitespace and
  attribute layout only, no behavior changes).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/components/PromptModal.vue

@@ -43,28 +43,10 @@ function onKeydown(e) {
 </script>
 
 <template>
-  <a-modal
-    :open="open"
-    :title="title"
-    :ok-text="okText"
-    cancel-text="Cancel"
-    :mask-closable="false"
-    :confirm-loading="loading"
-    @ok="ok"
-    @cancel="close"
-  >
-    <a-textarea
-      v-if="type === 'textarea'"
-      v-model:value="value"
-      :auto-size="{ minRows: 10, maxRows: 20 }"
-      autofocus
-      @keydown="onKeydown"
-    />
-    <a-input
-      v-else
-      v-model:value="value"
-      autofocus
-      @keydown="onKeydown"
-    />
+  <a-modal :open="open" :title="title" :ok-text="okText" cancel-text="Cancel" :mask-closable="false"
+    :confirm-loading="loading" @ok="ok" @cancel="close">
+    <a-textarea v-if="type === 'textarea'" v-model:value="value" :auto-size="{ minRows: 10, maxRows: 20 }" autofocus
+      @keydown="onKeydown" />
+    <a-input v-else v-model:value="value" autofocus @keydown="onKeydown" />
   </a-modal>
 </template>