git-subagent-sync

Synchronize subagent changes to git on shared trunk across all lanes and all untracked WIP by default (or scoped via --lane/--paths). Enforces single-source invariants, safe merge convergence via fak sync check, fak sync reconcile --apply, and fak sync push, dual-repo synchronization (fak & fak-private), disjoint file-tree fencing via dos arbitrate, detached build-isolation worktrees, and atomic coordinator landing…