Copilot instructions

1This is a TypeScript project that implements a frontend build tooling called Vite. Please follow these guidelines when contributing:
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3## Code Standards
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5- Run `pnpm run lint` to ensure that your code adheres to the code standards.
6- Run `pnpm run format` to format your code.
7- Build: `pnpm run build`
8- Test: `pnpm run test` (uses Vitest and Playwright)
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10## Repository Structure
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12- `docs/`: Documentation
13- `packages/create-vite`: The source code for the `create-vite` command
14- `packages/plugin-legacy`: The source code for the `@vitejs/plugin-legacy` plugin
15- `packages/vite`: The source code for the Vite core
16- `playground/`: E2E tests
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18## PR Guidelines
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20### PR Title & Commit Messages
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22- Follow the [commit message convention](./commit-convention.md)
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24### PR Description
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26- What does this PR solve? - Clear problem/feature description
27- Why was this approach chosen? - Implementation rationale
28- If this is a new feature, include a convincing reason.
29- If this adds a new config option, verify problem can't be solved with smarter defaults, existing options, or a plugin
30- If this is a bug fix, explain what caused the bug - Link to relevant code if possible
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32### Code Style & Standards
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34- Code follows TypeScript best practices
35- Maintains existing code structure and organization
36- Comments explain "why", not "what"
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38### Testing
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40- Prefer unit tests if it can be tested without using mocks
41- E2E tests should be added in the `playground/` directory
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43### Documentation
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45- Update documentation for public API changes
46- Documentation changes go in `docs/` folder
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48### Other Considerations
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50- No concerning performance impacts
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