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/SettingListItem.vue

@@ -19,8 +19,12 @@ const padding = computed(() =>
     <a-row :gutter="[8, 16]">
       <a-col :xs="24" :lg="12">
         <a-list-item-meta>
-          <template #title><slot name="title" /></template>
-          <template #description><slot name="description" /></template>
+          <template #title>
+            <slot name="title" />
+          </template>
+          <template #description>
+            <slot name="description" />
+          </template>
         </a-list-item-meta>
       </a-col>
       <a-col :xs="24" :lg="12">