Add Vercel domain verification configuration

domains/_vercel.sahnoun.json

@@ -0,0 +1,9 @@
+{
+  "owner": {
+    "username": "ENSI-Sahnoun",
+    "email": "work@sahnoun.dev"
+  },
+  "records": {
+    "TXT": "vc-domain-verify=sahnoun.is-a.dev,7b378c4204525dccd010"
+  }
+}