Add IONOS DNS provider

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker/caddy/Dockerfile

@@ -18,6 +18,7 @@ RUN GOPROXY=direct xcaddy build \
     --with github.com/caddy-dns/godaddy \
     --with github.com/caddy-dns/namecheap \
     --with github.com/caddy-dns/ovh \
+    --with github.com/caddy-dns/ionos \
     --with github.com/caddy-dns/linode \
     --with github.com/mholt/caddy-l4 \
     --with github.com/fuomag9/caddy-blocker-plugin \

src/lib/dns-providers.ts

@@ -170,6 +170,16 @@ export const DNS_PROVIDERS: DnsProviderDefinition[] = [
       { key: "consumer_key", label: "Consumer Key", type: "password", required: true },
     ],
   },
+  {
+    name: "ionos",
+    displayName: "IONOS",
+    description: "IONOS DNS API",
+    docsUrl: "https://github.com/caddy-dns/ionos",
+    modulePath: "github.com/caddy-dns/ionos",
+    fields: [
+      { key: "api_token", label: "API Token", type: "password", required: true, placeholder: "prefix.secret" },
+    ],
+  },
   {
     name: "linode",
     displayName: "Linode (Akamai)",