feat: register lijo.is-a.dev subdomain pointing to Firebase Hosting

Adds the domain configuration file to claim the 'lijo.is-a.dev'
subdomain.

- Formats metadata to align strictly with the repository's database
schema.
- Establishes ownership via GitHub profile validation hooks.
- Provisions a CNAME alias pointing directly to the target Next.js
production deployment layer at 'my-eng-blog.web.app'.

domains/lijo.json

@@ -0,0 +1,9 @@
+{
+  "owner": {
+    "username": "lijojosef",
+    "email": "lijojoseph234@gmail.com"
+  },
+  "records": {
+    "CNAME": "my-eng-blog.web.app"
+  }
+}