Clear all undo/redo history
Push the current state before making a change. Call this BEFORE modifying nodes/connections so the previous state is saved.
Redo the last undone change. Returns the restored state snapshot. The caller must pass the CURRENT state so it can be pushed to undo.
Undo the last change. Returns the previous state snapshot. The caller must pass the CURRENT state so it can be pushed to redo.
Snapshot-based undo/redo state management for the flow editor. Stores complete state snapshots on each change for reliable undo/redo.