Libraries

Note	Draft placeholder — outline notes only; prose not yet written.

Points this section needs to cover:

When to use a library instead of shelling out to the git binary
libgit2 and its language bindings (Rust git2-rs, Python pygit2, Go git2go, Node nodegit, Ruby Rugged)
JGit (Java), go-git (pure Go), Dulwich (pure Python)
gitoxide (gix, Rust) — new since the 2nd edition
Per-library SHA-256 object-format support status — a real concern during the 3.0 transition