Build an Inventory Management Service

Problem/Feature Description

A warehouse company needs a Spring Boot service to track product inventory across multiple warehouse locations. Build it with Spring Boot 3 and Java 17+.

Domain concepts:

• Product: id, sku (unique), name, description, category, weightGrams
• Warehouse: id, name, location, capacity
• InventoryRecord: id, productId, warehouseId, quantity, lastUpdated

Endpoints:

• POST /api/products -- create a product (sku must be unique, name required)
• GET /api/products -- list products, optional filter by category
• GET /api/products/:id -- get product details
• POST /api/warehouses -- register a warehouse
• GET /api/warehouses -- list all warehouses
• POST /api/inventory/receive -- receive stock (productId, warehouseId, quantity to add)
• POST /api/inventory/transfer -- transfer stock between warehouses (productId, fromWarehouseId, toWarehouseId, quantity)
• GET /api/inventory/product/:productId -- get stock levels across all warehouses for a product

Business rules:

• SKU must be unique across all products
• Cannot transfer more stock than available in the source warehouse
• Receiving stock creates or updates the inventory record
• Transfer is atomic — deduct from source and add to destination

Use PostgreSQL for the database.

Output Specification

Produce a complete Spring Boot project with:

• Main application class
• All Java source files for the domain logic
• Configuration files
• Database schema/migrations
• Test classes covering at least inventory receive and transfer operations
• pom.xml with dependencies

You may create additional files as needed.