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/StatusBadge.vue

@@ -0,0 +1,30 @@
+<template>
+  <span :class="classes" class="inline-flex items-center rounded-full px-2.5 py-0.5 text-xs font-semibold uppercase tracking-wide">
+    {{ label }}
+  </span>
+</template>
+
+<script setup lang="ts">
+import type { CheckStatus } from '~/types/dns'
+
+const props = defineProps<{
+  status: CheckStatus
+}>()
+
+const classes = computed(() => {
+  switch (props.status) {
+    case 'pass':
+      return 'bg-green-100 text-green-800 dark:bg-green-900/30 dark:text-green-400'
+    case 'warn':
+      return 'bg-yellow-100 text-yellow-800 dark:bg-yellow-900/30 dark:text-yellow-400'
+    case 'fail':
+      return 'bg-red-100 text-red-800 dark:bg-red-900/30 dark:text-red-400'
+    case 'info':
+      return 'bg-blue-100 text-blue-800 dark:bg-blue-900/30 dark:text-blue-400'
+    default:
+      return 'bg-gray-100 text-gray-800 dark:bg-gray-800 dark:text-gray-400'
+  }
+})
+
+const label = computed(() => props.status)
+</script>