feat(dns): add built-in dcrouter DNS provider support and rename manual domains to dcrouter-hosted/local

ts/dns/providers/factory.ts

@@ -38,6 +38,17 @@ export function createDnsProvider(
       }
       return new CloudflareDnsProvider(credentials.apiToken);
     }
+    case 'dcrouter': {
+      // The built-in DcRouter pseudo-provider has no runtime client — dcrouter
+      // itself serves the records via the embedded smartdns.DnsServer. This
+      // case exists only to satisfy the exhaustive switch; it should never
+      // actually run because the handler layer rejects any CRUD that would
+      // result in a DnsProviderDoc with type: 'dcrouter'.
+      throw new Error(
+        `createDnsProvider: 'dcrouter' is a built-in pseudo-provider — no runtime client exists. ` +
+          `This call indicates a DnsProviderDoc with type: 'dcrouter' was persisted, which should never happen.`,
+      );
+    }
     default: {
       // If you see a TypeScript error here after extending TDnsProviderType,
       // add a `case` for the new type above. The `never` enforces exhaustiveness.