Complete the Git commands: Git Multi-Pack Index: Indexing Multiple Packfiles

Create a disposable repository with enough commits to produce a set of objects, create multiple packfiles in the lab, and run `git count-objects -v` before creating a MIDX. Run `git multi-pack-index write`, confirm the MIDX exists, and run `git multi-pack-index verify`. Then run `git multi-pack-index repack --batch-size=1m`, followed by `git multi-pack-index expire` and another `git multi-pack-index verify`. Record the number of packfiles before and after the MIDX operations and explain why creating a MIDX is different from merging all objects into one pack. Finish with `git fsck --full` and explain why MIDX verification and object-integrity checking answer different questions. This lesson uses only official Git project documentation for command semantics: `git-multi-pack-index`, `gitformat-pack`, `git-repack`, `git-fsck`, and the Git 2.56.0 command index. No third-party Git documentation is used for command semantics.