1132e0999b
- product table (catalog definition, no cost column — cost tracked per receipt/unit) - inventory_unit table (serialized items with serial number, condition, status) - stock_receipt table (FIFO cost tracking — records every stock receive event with cost_per_unit, supplier, date) - price_history table (logs every retail price change for margin analysis over time) - product_supplier join table (many-to-many, tracks supplier SKU and preferred supplier) - Full CRUD routes + search (name, SKU, UPC, brand) - Inventory unit routes nested under products - Price changes auto-logged on product update - 33 tests passing