- Add backend API routes for remote commit lists (local-ahead, remote-ahead, all commits by branch)
- Surface ahead/behind commit counts and expandable commit lists in Remotes tab UI
- Add expand/collapse rows showing commit hash, message, author, and relative date
- Style commit list rows with alternating backgrounds and monospace hashes
- Add comprehensive tests for API routes and GitManagerModal component
- Update README documentation for Git Manager Remotes tab