feat(24-01): install AWS Route 53 SDK and create dedicated schema migration

- Add @aws-sdk/client-route-53 dependency (official aws-sdk-js-v3 package)
- Add migrations/102_route53_tables.sql: route53_zones, route53_records,
  route53_record_history (D-06 change ledger), route53_audit_log
  (D-03/D-07 attempt audit log with pending/committed/failed status)
- Seed integration_settings row for key='route53' (D-10, display-only toggle)
- Unbounded retention by design (D-08) — no purge job, no TTL, no DELETE

package.json

@@ -12,6 +12,7 @@
   },
   "dependencies": {
     "@anthropic-ai/sdk": "^0.91.1",
+    "@aws-sdk/client-route-53": "^3.1104.0",
     "@better-auth/cli": "^1.4.10",
     "@hookform/resolvers": "^5.2.2",
     "@radix-ui/react-accordion": "^1.2.12",