Stage 8: Let Spring supply a product-file reader
JDK 21+; Maven 3.9+.
Open the folder containing pom.xml.
Run: mvn spring-boot:run
Open: http://localhost:8086/products
Stop: Ctrl+C
Complete explanations and all source: README.html
Expected: Open /products: 30 product rows. Open /products/1: full details. Repeated list requests print the same reader identity. /products/99999 returns 404.
