Build an Inventory Tracking API

Problem/Feature Description

A warehouse needs an API to track product inventory. Build it using Hono and TypeScript, targeting Bun. The API should support CRUD operations on products and inventory adjustment transactions.

Endpoints:

• POST /api/products -- create a product (fields: sku, name, category, initialStock)
• GET /api/products -- list all products with current stock levels
• GET /api/products/:id -- get a single product
• PATCH /api/products/:id -- update product name or category
• POST /api/products/:id/adjust -- adjust stock (fields: quantity which can be positive or negative, reason)
• GET /api/products/:id/history -- get adjustment history for a product

Business rules:

• SKU must be unique, uppercase, 3-20 characters
• Initial stock must be a non-negative integer
• Stock adjustment cannot bring total below zero
• Reason is required for every adjustment
• Each adjustment records a timestamp

Use in-memory storage.

Output Specification

Produce:

• src/app.ts -- Hono application
• src/index.ts -- Bun entry point
• src/routes/products.ts -- product endpoints
• src/routes/adjustments.ts -- stock adjustment endpoints
• src/schemas.ts -- Zod validation schemas
• package.json -- with dependencies (no need to install)

You may create additional files as needed.