Add .env.example template with environment variables documentation

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

.env.example

@@ -0,0 +1,19 @@
+# Database
+DATABASE_URL="postgresql://user:password@localhost:5432/dashboard_desa?schema=public"
+
+# Authentication
+BETTER_AUTH_SECRET="your-secret-key-here-min-32-characters"
+ADMIN_EMAIL="admin@example.com"
+ADMIN_PASSWORD="admin123"
+
+# GitHub OAuth (Optional)
+GITHUB_CLIENT_ID=""
+GITHUB_CLIENT_SECRET=""
+
+# Application
+PORT=3000
+NODE_ENV=development
+LOG_LEVEL=info
+
+# Public URL
+VITE_PUBLIC_URL="http://localhost:3000"

.gitignore

@@ -16,6 +16,7 @@ _.log
 report.[0-9]_.[0-9]_.[0-9]_.[0-9]_.json
 
 # dotenv environment variable files
+# Only .env.example is allowed to be committed
 .env
 .env.development.local
 .env.test.local