RiverEditorState nutzt dieselben SharedInput-Flags wie der Wasserfall-Editor (finalizeWaterfallRequested, cancelZoneDrawing, deleteWaterfallRequested, undoWaterfallPointRequested), aber LAYER_RIVER fehlte in allen vier Key-Handler-Zweigen in EditorApp.handleKeyPress. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>