refactor: finalize firebase purge and consolidate supabase auth layer

Author: EmiyaKiritsugu3

.antigravityignore

@@ -4,13 +4,6 @@
 # Copy this file to .env.local and fill in the values.
 # DO NOT commit the .env.local file to source control.
 
-# Firebase (Legacy - Auth)
-NEXT_PUBLIC_FIREBASE_API_KEY=
-NEXT_PUBLIC_FIREBASE_AUTH_DOMAIN=
-NEXT_PUBLIC_FIREBASE_PROJECT_ID=
-NEXT_PUBLIC_FIREBASE_STORAGE_BUCKET=
-NEXT_PUBLIC_FIREBASE_MESSAGING_SENDER_ID=
-NEXT_PUBLIC_FIREBASE_APP_ID=
 
 # Supabase (PostgreSQL & New Auth)
 NEXT_PUBLIC_SUPABASE_URL=

.env.example

@@ -34,11 +34,11 @@ typecheck_details.txt
 .stylelintcache
 .turbo/
 
-# Vercel & Firebase
+# Antigravity & Agents
+.antigravityignore
+
+# Vercel
 .vercel
-.firebase
-firebase-debug.log
-database-debug.log
 
 # Environment variables
 .env