Environment Reproducibility: Lockfiles & Docker

Day 27 of 100 Days of MLOps. You've pinned code, data and config — but the environment itself can still change your results. Lock your dependencies and prove it by rebuilding the environment from scratch to get the identical model, then take it further with Docker so the whole OS + Python + libraries travel together: 'works on my machine' becomes 'works on every machine.' Runs 100% locally on any OS.