diff --git a/infra/cdk.context.json b/infra/cdk.context.json
index 2145e1d..ad650bc 100644
--- a/infra/cdk.context.json
+++ b/infra/cdk.context.json
@@ -1,5 +1,5 @@
 {
-  "availability-zones:account=328440206208:region=us-east-1": [
+  "availability-zones:account=011934824531:region=us-east-1": [
     "us-east-1a",
     "us-east-1b",
     "us-east-1c",
diff --git a/infra/lib/foundation-stack.ts b/infra/lib/foundation-stack.ts
index c5bb5ef..16ade07 100644
--- a/infra/lib/foundation-stack.ts
+++ b/infra/lib/foundation-stack.ts
@@ -105,7 +105,10 @@ export class FoundationStack extends cdk.Stack {
       serverlessV2MaxCapacity: 4,
       enableDataApi: true,
       storageEncrypted: true,
-      backup: { retention: cdk.Duration.days(7) },
+      // Aurora native automated backups (PITR). 14-day retention for the prod tenant;
+      // a dedicated AWS Backup vault + cross-account restore test is a tracked follow-up
+      // (no org central-backup design exists yet — see the prod-deploy plan Phase 4 fallback).
+      backup: { retention: cdk.Duration.days(14), preferredWindow: '07:00-08:00' },
       deletionProtection: config.retainData,
       removalPolicy: config.retainData ? cdk.RemovalPolicy.RETAIN : cdk.RemovalPolicy.DESTROY,
       defaultDatabaseName: 'proposals',