security: remove .env from git tracking and add to .gitignore

BREAKING CHANGE: .env file is no longer tracked in git for security.
Each environment must maintain its own .env file with secrets.
Use .env.example as a template.

.env

@@ -1,18 +0,0 @@
-DATABASE_URL="mysql://lists_app:ListsApp@2025!@192.168.4.20:3306/ultimate_lists"
-
-# NextAuth Configuration
-AUTH_URL=http://localhost:3500
-NEXTAUTH_URL=http://localhost:3500
-NEXTAUTH_SECRET=your-secret-key-here-please-change-in-production
-AUTH_SECRET=your-secret-key-here-please-change-in-production
-AUTH_TRUST_HOST=true
-
-# Database connection check (for docker-compose health check)
-DB_HOST=192.168.4.20
-DB_PORT=3306
-DB_USER=lists_app
-DB_PASSWORD=ListsApp@2025!
-
-VAPID_PUBLIC_KEY=BF_5O2UOhLf4Ax45p4fV7E6r0CxIok7X9uxnXKMzJU6XEN2i5s5eq84n9u34jM7Cv3TrRJFXUuickZy-8uQLdhc
-VAPID_PRIVATE_KEY=cllNiZXE0jc791vU_UpV42sclYWiVy7dm0zI9OvaAP4
-VAPID_SUBJECT=mailto:your-email@example.com

.gitignore

@@ -23,6 +23,7 @@ yarn-debug.log*
 yarn-error.log*
 
 # Local env files
+.env
 .env*.local
 
 # Vercel