Update .env.example with all variables and simplify .gitignore

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.env.example

@@ -4,3 +4,18 @@ NODE_ENV=development
 
 # Dev Inspector
 REACT_EDITOR=code
+
+# Database
+DATABASE_URL=postgresql://user:password@localhost:5432/base-template
+DIRECT_URL=postgresql://user:password@localhost:5432/base-template
+
+# Google OAuth
+GOOGLE_CLIENT_ID=
+GOOGLE_CLIENT_SECRET=
+
+# Role
+SUPER_ADMIN_EMAIL=admin@example.com
+
+# Telegram Notification (optional)
+TELEGRAM_NOTIFY_TOKEN=
+TELEGRAM_NOTIFY_CHAT_ID=