feat: jest

[Dogtiti]

💻 变更类型 | Change Type

• [x] feat
• [ ] fix
• [ ] refactor
• [ ] perf
• [ ] style
• [x] test
• [ ] docs
• [ ] ci
• [ ] chore
• [ ] build

🔀 变更说明 | Description of Change

📝 补充信息 | Additional Information

Summary by CodeRabbit

• New Features

  • Introduced a Jest configuration for seamless testing in Next.js applications, including support for JavaScript and TypeScript files.
  • Added a setup file that enhances Jest with additional matchers for improved DOM testing.
  • Implemented a simple sum function with accompanying tests to ensure correctness.

• Enhancements

  • Added new scripts in the project configuration for improved testing capabilities, including interactive and CI testing.
  • Included essential testing libraries to enhance the development experience and maintain code quality.