fix: use correct Vercel verification token scoped to mrinal.is-a.dev

Copilot review on PR #37443 caught that the previous TXT was scoped to
is-a.dev (apex) instead of mrinal.is-a.dev. Re-attached the domain
to the Vercel project and replaced the TXT with the correctly-scoped
token so domain verification will succeed once DNS propagates.

domains/_vercel.mrinal.json

@@ -4,6 +4,6 @@
     "email": "mrinaljoshi27@gmail.com"
   },
   "records": {
-    "TXT": "vc-domain-verify=is-a.dev,9832888dad2c15eabf5a"
+    "TXT": "vc-domain-verify=mrinal.is-a.dev,3bd0a4301d97ea5eda48"
   }
 }