Built a Linux container by hand this weekend, just for learning (no Docker/Podman)

Nothing groundbreaking here honestly, plenty of folks have done this before me, just did it purely for the learning, wanted to actually understand what docker run does under the hood instead of taking it for granted like I always have. Had to run it inside a lima VM on macOS since Darwin doesn't have namespaces/cgroups natively, then built the whole thing piece by piece, OverlayFS for the image layers, unshare for the namespaces,