JSIT

* Object storage logic, crucial for the VCS, is dangerously duplicated across multiple files, seriously impeding maintainability and consistency. * The current index implementation is fundamentally fragile, relying on simple text files rather than robust binary staging metadata tracking. * Refactor synchronous file system operations (e.g., `fs.readFileSync`) to asynchronous I/O for scalable performance during staging large files. * Centralize core utilities like object hashing, path resolution, and directory management to eliminate the observed code smell and redundancy. * The structural separation between `src/git.js` and `src/commands` requires remediation to prevent the inconsistent object storage implementations.