Build git 2.54 from source and add hook subcommand

Build git 2.54 from source and add hook subcommand

Debian bookworm ships git 2.39 but we need 2.54+ for
hook.<name>.command config support, which lets quire register
hooks via git config instead of writing shim scripts to disk.

The hook subcommand is a no-op that logs invocations — enough to
verify the dispatch path works end-to-end.

Assisted-by: GLM-5.1 via pi