Initial commit: DNS Test - DNS health checking tool

Go backend (miekg/dns) + Nuxt 3 frontend (Tailwind CSS v4).

8 check categories, 52 checks total:
- Overview: @ record, WWW, MX with ASN/provider lookup
- Domain Registration: expiry, registrar (RDAP + whois fallback)
- Parent Delegation: NS records, glue, consistency
- Nameservers: 17 checks (reachability, auth, recursion, TCP/UDP, AXFR, etc.)
- SOA: serial consistency, timing values
- Mail (MX): 11 checks (CNAME, PTR, public IPs, consistency)
- Mail Auth: SPF, DKIM, DMARC
- WWW: A record, CNAME

Features:
- SSE streaming (results appear as each category completes)
- SQLite history (modernc.org/sqlite)
- Rate limiting, CORS, request logging
- Dark mode, responsive design

frontend/app/components/CheckResult.vue

@@ -0,0 +1,74 @@
+<template>
+  <div class="border-b border-gray-100 last:border-b-0 dark:border-gray-800">
+    <div
+      class="flex items-start gap-3 px-4"
+      :class="[
+        compact ? 'py-2' : 'py-3',
+        hasDetails ? 'cursor-pointer hover:bg-gray-50 dark:hover:bg-gray-800/50' : 'cursor-default'
+      ]"
+      @click="hasDetails && (detailsOpen = !detailsOpen)"
+    >
+      <div class="mt-0.5 shrink-0" v-if="!compact">
+        <StatusBadge :status="check.status" />
+      </div>
+      <div v-else class="mt-1.5 shrink-0">
+        <span class="inline-block h-1.5 w-1.5 rounded-full"
+          :class="{
+            'bg-green-500': check.status === 'pass',
+            'bg-blue-500': check.status === 'info',
+          }"
+        ></span>
+      </div>
+      <div class="min-w-0 flex-1">
+        <div class="flex items-baseline justify-between gap-2">
+          <h4 :class="compact ? 'text-xs text-gray-700 dark:text-gray-300' : 'text-sm font-medium text-gray-900 dark:text-white'">
+            {{ check.title }}
+            <span v-if="compact" class="text-gray-400 dark:text-gray-500"> — {{ check.message }}</span>
+          </h4>
+        </div>
+        <p v-if="!compact" class="mt-0.5 text-sm text-gray-600 dark:text-gray-400">{{ check.message }}</p>
+      </div>
+      <div v-if="hasDetails && !compact" class="mt-1 shrink-0 text-gray-400 dark:text-gray-500">
+        <svg
+          xmlns="http://www.w3.org/2000/svg"
+          class="h-4 w-4 transition-transform"
+          :class="{ 'rotate-180': detailsOpen }"
+          fill="none"
+          viewBox="0 0 24 24"
+          stroke="currentColor"
+          stroke-width="2"
+        >
+          <path stroke-linecap="round" stroke-linejoin="round" d="M19 9l-7 7-7-7" />
+        </svg>
+      </div>
+    </div>
+    <div v-if="detailsOpen && hasDetails" class="border-t border-gray-100 bg-gray-50 px-4 py-3 dark:border-gray-800 dark:bg-gray-800/30">
+      <ul class="space-y-1">
+        <li
+          v-for="(detail, i) in check.details"
+          :key="i"
+          class="flex items-start gap-2 text-sm text-gray-600 dark:text-gray-400"
+        >
+          <span class="mt-1.5 inline-block h-1.5 w-1.5 shrink-0 rounded-full bg-gray-400 dark:bg-gray-500"></span>
+          <span class="font-mono text-xs leading-relaxed">{{ detail }}</span>
+        </li>
+      </ul>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import type { CheckResult as CheckResultType } from '~/types/dns'
+
+const props = withDefaults(defineProps<{
+  check: CheckResultType
+  defaultExpanded?: boolean
+  compact?: boolean
+}>(), {
+  defaultExpanded: false,
+  compact: false,
+})
+
+const detailsOpen = ref(props.defaultExpanded)
+const hasDetails = computed(() => props.check.details && props.check.details.length > 0)
+</script>