Code Migration Helpers

A CLI toolset (v0.6.1) to automate common code migration tasks: adding extensions to relative imports (e.g., converting `./file` to `./file.js`), migrating Jest test constructs to Vitest (replacing `jest.fn()` with `vi.fn()`), and renaming file extensions (e.g., `.js` → `.cjs`). Designed for Node.js 18+ with a file-based scope; output may not be 100% accurate—always review changes. Lightweight alternative to codemods or jscodeshift for these specific patterns.