pub fn acquire_project(project_root: &Path) -> Result<LockGuard, LockError>Expand description
Acquire the short-held, project-wide lock that serializes mutations of the primary checkout (version-bump commits/tags, docs commits, branch integration/cleanup) across concurrently finishing phases (13-DEFERRED-CR-03 fix shape #3).
This is the second level of the two-level model: per-phase locks guard a phase’s own advance (held across gate-days), while this coarse lock guards the shared git checkout and is held for seconds. It must NEVER be held across a gate wait.