Every store writer serializes on an exclusive flock held open-to-commit (released before autosync and the drift advisory). A checkout's store_location section is resolved in one place; open --store PATH creates a detached working tree, and probeRoot accepts a checkout whose pointer resolves. Store-scoped verbs (pack, shun, serve) follow the pointer end to end. check-in: 94d4659a53 user: dmestas tags: worktrees