feat: Add email signing DNS records for sam2-saas-prod

- Update main domain with MX, SPF, and DMARC records for Resend
- Add DKIM subdomain record for email signing verification
- Add DMARC policy subdomain record for authentication
- Required for production email verification and Google OAuth

domains/_dmarc.sam2-saas-prod.is-not-a.dev.json

@@ -0,0 +1,15 @@
+{
+  "description": "DMARC record for email authentication policy - SAM2 SaaS Production",
+  "domain": "is-not-a.dev",
+  "subdomain": "_dmarc.sam2-saas-prod",
+  "owner": {
+    "repo": "https://github.com/devtony01/sam2-saas-concept",
+    "email": "chibuezeogbuji01@gmail.com"
+  },
+  "record": {
+    "TXT": [
+      "v=DMARC1; p=none;"
+    ]
+  },
+  "proxied": false
+}

domains/resend._domainkey.sam2-saas-prod.is-not-a.dev.json

@@ -0,0 +1,15 @@
+{
+  "description": "DKIM record for Resend email signing - SAM2 SaaS Production",
+  "domain": "is-not-a.dev",
+  "subdomain": "resend._domainkey.sam2-saas-prod",
+  "owner": {
+    "repo": "https://github.com/devtony01/sam2-saas-concept",
+    "email": "chibuezeogbuji01@gmail.com"
+  },
+  "record": {
+    "TXT": [
+      "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDfVM4sMAa9ppIBm+D8SLRZsnEV+JWsWu4CBTCxOyzYTDN8X5tkBCueZrIQKkyy31pM72MMVvASkqOFBO+PmVI5hDxxI3+RZ5QeojSMrkm6kWa8Lz2XafYPv1NgHHGuGSoGhiYOIxqFCEytxnZurqtSy/C0E+Qx2zs9AaUbDObXVwIDAQAB"
+    ]
+  },
+  "proxied": false
+}

domains/sam2-saas-prod.is-not-a.dev.json

@@ -7,7 +7,17 @@
     "email": "chibuezeogbuji01@gmail.com"
   },
   "record": {
-    "CNAME": "a50df0d491cd74be0a95d0fbc5535687-50644910.us-east-1.elb.amazonaws.com"
+    "CNAME": "a50df0d491cd74be0a95d0fbc5535687-50644910.us-east-1.elb.amazonaws.com",
+    "MX": [
+      {
+        "priority": 10,
+        "value": "feedback-smtp.us-east-1.amazonses.com"
+      }
+    ],
+    "TXT": [
+      "v=spf1 include:amazonses.com ~all",
+      "v=DMARC1; p=none;"
+    ]
   },
   "proxied": false
 }