Fix runtime error

.env.example

@@ -0,0 +1,17 @@
+# Server Configuration
+PORT=3000
+WDS_SOCKET_PORT=443
+
+# Backend API URL
+REACT_APP_BACKEND_URL=http://localhost:8000
+
+# App Base Path Configuration
+# Examples:
+# - For root path: REACT_APP_BASENAME=
+# - For subpath: REACT_APP_BASENAME=/membership
+# - For production: REACT_APP_BASENAME=/membership
+REACT_APP_BASENAME=
+
+# Feature Flags
+REACT_APP_ENABLE_VISUAL_EDITS=false
+ENABLE_HEALTH_CHECK=false