Thrown when a guard deploy fails after its state move committed and the
engine could not cleanly undo the result — any of: the rollback write itself
failed; the move created sibling docs (spawn) that a parent-only rollback
cannot undo; or a multi-guard deploy partially applied, so even a clean state
rollback leaves the earlier guards orphaned (PartialGuardDeployError).
The workflow's persisted state and its deployed guards are now divergent and
need manual reconciliation; the engine screams rather than leaving the
inconsistency silent.
Thrown when a guard deploy fails after its state move committed and the engine could not cleanly undo the result — any of: the rollback write itself failed; the move created sibling docs (spawn) that a parent-only rollback cannot undo; or a multi-guard deploy partially applied, so even a clean state rollback leaves the earlier guards orphaned (PartialGuardDeployError). The workflow's persisted state and its deployed guards are now divergent and need manual reconciliation; the engine screams rather than leaving the inconsistency silent.