task(A4.11): documentService singleton + global v2 undo/redo shortcuts

frontend/src/components/CanvasArea.tsx

@@ -16,6 +16,7 @@ import { InteractionDispatcher } from '../interaction/dispatcher';
 import { logger } from '../utils/logger';
 import { CADDocument } from '../kernel/document/CADDocument';
 import { YjsDocument } from '../crdt/YjsDocument';
+import { setActiveDocument, getActiveDocument } from '../kernel/document/documentService';
 import { pluginRegistry } from '../plugins';
 
 const CanvasArea: React.FC<CanvasAreaProps> = ({
@@ -62,6 +63,8 @@ const CanvasArea: React.FC<CanvasAreaProps> = ({
         color: '#ffffff', lineType: 'solid', transparency: 0, sortOrder: 0, parentId: null,
       } as never);
       const v2Doc = new CADDocument(ydoc);
+      // App-Level-Zugriffspunkt für HistoryPanel/Tastenkürzel (Task A4.11):
+      setActiveDocument(v2Doc);
       // Committete V2-Elemente fließen über den etablierten Kanal in UI/State:
       v2Doc.onChanged(() => {
         for (const el of v2Doc.getAllElements()) {
@@ -112,6 +115,7 @@ const CanvasArea: React.FC<CanvasAreaProps> = ({
       interaction.detach();
       dispatcherRef.current?.destroy();
       dispatcherRef.current = null;
+      setActiveDocument(null);
       zoomPanRef.current = null;
       renderEngineRef.current = null;
       interactionRef.current = null;
@@ -283,6 +287,26 @@ const CanvasArea: React.FC<CanvasAreaProps> = ({
   // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [activeTool]);
 
+  // Task A4.11: Globale Undo/Redo-Shortcuts wirken nur auf das V2-Dokument,
+  // wenn es registriert ist (= Flag aktiv). Legacy-History bleibt unberührt.
+  useEffect(() => {
+    const onKey = (e: KeyboardEvent) => {
+      if (!(e.ctrlKey || e.metaKey)) return;
+      const doc = getActiveDocument();
+      if (!doc) return; // Flag aus → Legacy-Verhalten unangetastet
+      const key = e.key.toLowerCase();
+      if (key === 'z' && !e.shiftKey) {
+        e.preventDefault();
+        if (doc.undo()) logger.info('V2 undo');
+      } else if (key === 'y' || (key === 'z' && e.shiftKey)) {
+        e.preventDefault();
+        if (doc.redo()) logger.info('V2 redo');
+      }
+    };
+    window.addEventListener('keydown', onKey);
+    return () => window.removeEventListener('keydown', onKey);
+  }, []);
+
   // Sync selected template to interaction engine
   useEffect(() => {
     const interaction = interactionRef.current;