feat(routes,email): persist system DNS routes with runtime hydration and add reusable email ops DNS helpers

ts/email/email-dns-records.ts

@@ -0,0 +1,53 @@
+import type {
+  IEmailDnsRecord,
+  TDnsRecordStatus,
+} from '../../ts_interfaces/data/email-domain.js';
+
+type TEmailDnsStatusKey = 'mx' | 'spf' | 'dkim' | 'dmarc';
+
+export interface IBuildEmailDnsRecordsOptions {
+  domain: string;
+  hostname: string;
+  selector?: string;
+  dkimValue?: string;
+  mxPriority?: number;
+  dmarcPolicy?: string;
+  dmarcRua?: string;
+  statuses?: Partial<Record<TEmailDnsStatusKey, TDnsRecordStatus>>;
+}
+
+export function buildEmailDnsRecords(options: IBuildEmailDnsRecordsOptions): IEmailDnsRecord[] {
+  const statusFor = (key: TEmailDnsStatusKey): TDnsRecordStatus => options.statuses?.[key] ?? 'unchecked';
+  const selector = options.selector || 'default';
+  const records: IEmailDnsRecord[] = [
+    {
+      type: 'MX',
+      name: options.domain,
+      value: `${options.mxPriority ?? 10} ${options.hostname}`,
+      status: statusFor('mx'),
+    },
+    {
+      type: 'TXT',
+      name: options.domain,
+      value: 'v=spf1 a mx ~all',
+      status: statusFor('spf'),
+    },
+    {
+      type: 'TXT',
+      name: `_dmarc.${options.domain}`,
+      value: `v=DMARC1; p=${options.dmarcPolicy ?? 'none'}; rua=mailto:${options.dmarcRua ?? `dmarc@${options.domain}`}`,
+      status: statusFor('dmarc'),
+    },
+  ];
+
+  if (options.dkimValue) {
+    records.splice(2, 0, {
+      type: 'TXT',
+      name: `${selector}._domainkey.${options.domain}`,
+      value: options.dkimValue,
+      status: statusFor('dkim'),
+    });
+  }
+
+  return records;
+}