docs: standardize documentation structure

- CLAUDE.md: universal development guidelines
- README.md: project description (consistent template)
- CONTRIBUTING.md: contribution workflow
- CHANGELOG.md: version history

Co-Authored-By: Svrnty Inc. <eng@svrnty.com>

CONTRIBUTING.md

@@ -0,0 +1,52 @@
+# Contributing
+
+Thank you for your interest in contributing to this project.
+
+## Development Guidelines
+
+See [CLAUDE.md](./CLAUDE.md) for development practices, engineering principles, and coding standards.
+
+## How to Contribute
+
+1. **Fork & Clone**
+   ```bash
+   git clone <your-fork-url>
+   cd <project>
+   git checkout JP
+   ```
+
+2. **Create a Branch**
+   ```bash
+   git checkout -b feature/your-feature-name
+   ```
+
+3. **Make Changes**
+   - Follow the guidelines in CLAUDE.md
+   - Keep changes focused and minimal
+   - Write tests if applicable
+
+4. **Validate**
+   - Run format checks
+   - Run lint checks
+   - Run test suite
+
+5. **Commit**
+   ```bash
+   git commit -m "feat: your change description"
+   ```
+
+   AI-authored commits must include:
+   ```
+   Co-Authored-By: Svrnty Inc. <eng@svrnty.com>
+   ```
+
+6. **Push & Create PR**
+   ```bash
+   git push origin feature/your-feature-name
+   ```
+   - Open a PR against the `JP` branch
+   - Provide clear description of changes
+
+## Questions?
+
+Open an issue for questions or discussions.