Shell-outs to git for status (porcelain v1/v2), unified-diff
parsing, and operations (stage, unstage, hunk-apply, discard,
commit, stash, log, pull, push). IPC verbs git.* registered on
the daemon dispatcher with git.changed event emission on
mutations. 42 new core tests.
Co-Authored-By: Claude <noreply@anthropic.com>