Undo the last N operations atomically. A recorded compound restores the
entire earlier graph and journal, including forgotten overlay records.
Other journal entries use the caller's inverse dispatcher. Returns the
number of mutation records reverted; a compound counts as one operation.
Allocated express IDs remain monotonic, so stale references cannot target
a different entity created after an undo.
Undo the last N operations atomically. A recorded compound restores the entire earlier graph and journal, including forgotten overlay records. Other journal entries use the caller's inverse dispatcher. Returns the number of mutation records reverted; a compound counts as one operation. Allocated express IDs remain monotonic, so stale references cannot target a different entity created after an undo.