chore(repo): enforce conventional commits

CLAUDE.md

@@ -31,8 +31,16 @@ npm run lint:fix         # Fix linting issues
 npm run format           # Format code with Prettier
 npm run format:check     # Check formatting without changes
 npm run type-check       # TypeScript type checking (no emit)
+npm run commitlint       # Validate the latest commit message
 ```
 
+## Commit Messages
+
+- Use [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) for every commit
+- Preferred format: `type(scope): description`
+- Common types: `feat`, `fix`, `docs`, `refactor`, `perf`, `test`, `chore`
+- The repository installs a `commit-msg` hook via `npm install`; do not bypass it unless explicitly required
+
 ### Testing Workflow
 
 - Tests use Vitest with `@cloudflare/vitest-pool-workers` for Workers-specific testing