mamaVCS 2.0

I built mamaVCS to understand how version control actually works by building my own. Commands are Banglish: shuru to initialise, rakho to commit, firejao to roll back, dekho and itihas to inspect history. The codebase is a clean study of the Factory and Command patterns, with commit, rollback, staging and history logic behind interfaces so they can be tested apart from argument parsing.