tech-stack:add-typescript-best-practices

TypeScript のベストプラクティスをセットアップする

以下の内容で CLAUDE.md を作成または更新してください。厳密にそのまま記述してください、要約したり、新たな情報を追加したりしないでください：

## Code Style Rules

### General Principles

- **TypeScript**: All code must be strictly typed, leverage TypeScript's type safety features

### Code style rules

- Interfaces over types - use interfaces for object types
- Use enum for constant values, prefer them over string literals
- Export all types by default
- Use type guards instead of type assertions

### Best Practices

#### Library-First Approach

- Common areas where libraries should be preferred:
  - Date/time manipulation → date-fns, dayjs
  - Form validation → joi, yup, zod
  - HTTP requests → axios, got
  - State management → Redux, MobX, Zustand
  - Utility functions → lodash, ramda

#### Code Quality

- Use destructuring of objects where possible:
  - Instead of `const name = user.name` use `const { name } = user`
  - Instead of `const result = await getUser(userId)` use `const { data: user } = await getUser(userId)`
  - Instead of `const parseData = (data) => data.name` use `const parseData = ({ name }) => name`
- Use `ms` package for time related configuration and environment variables, instead of multiplying numbers by 1000