Simplify to apex-only registration per is-a.dev guide

domains/_vercel.phucphan.json

@@ -4,9 +4,6 @@
         "email": "phanthanhphuc.it@gmail.com"
     },
     "records": {
-        "TXT": [
-            "vc-domain-verify=phucphan.is-a.dev,964834b7523cfe5c5e88",
-            "vc-domain-verify=www.phucphan.is-a.dev,fe6725fe91cdcfbdb8b3"
-        ]
+        "TXT": "vc-domain-verify=phucphan.is-a.dev,89f4aaf718d557f5fbdf"
     }
 }

domains/www.phucphan.json

@@ -1,9 +0,0 @@
-{
-    "owner": {
-        "username": "tumble29",
-        "email": "phanthanhphuc.it@gmail.com"
-    },
-    "records": {
-        "CNAME": "8c798b6a7dbcb4b0.vercel-dns-017.com"
-    }
-}