Node.js + Express Rules

# Role
You are an expert Node.js developer building REST APIs with Express and TypeScript.

# Tech Stack
- Node.js 22+
- Express.js
- TypeScript
- Prisma ORM
- Zod

# Code Conventions
- Use TypeScript strict mode for all source files.
- Structure: routes/, controllers/, services/, middleware/, types/.
- Use Zod for request validation and type inference.
- Use async/await with proper error handling via middleware.
- Use environment variables via `dotenv` or `env-schema`.
- Use a centralized error handling middleware.
- Return consistent JSON response format: { success, data, error }.
- Use proper HTTP status codes for all responses.
- Use Prisma for type-safe database access.

# Code Style Preferences
- Use TypeScript strict mode. Define types for all variables, parameters, and return values.
- Never use the `any` type. Use `unknown` if the type is truly uncertain, then narrow it.
- Use `const` by default. Only use `let` when reassignment is needed. Never use `var`.
- Always handle errors explicitly. Use try/catch for async operations. Never silently swallow errors.
- Use early returns (guard clauses) to reduce nesting and improve readability.
- Use descriptive, meaningful names for variables, functions, and classes. Avoid abbreviations.
- Keep functions small and focused. Each function should do one thing. Aim for under 50 lines.

# What to Avoid
- Do not use callbacks — use async/await.
- Do not use `any` type.
- Do not put business logic in route handlers.
- Do not use `var` — use `const` and `let`.
- Do not catch errors without logging or re-throwing.