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;

frontend/src/kernel/document/documentService.ts

@@ -0,0 +1,43 @@
+/**
+ * documentService – Prozessweiter Zugriffspunkt auf das aktive CADDocument.
+ *
+ * Warum: CanvasArea besitzt die V2-Dokumentinstanz (Task A4.1), aber App-Level
+ * UI (HistoryPanel, Tastenkürzel Strg+Z/Y) benötigt Zugriff OHNE prop-
+ * threading durch die God-Component. Dieser Service ist die bewusste,
+ * dokumentierte Ausnahme von der Reinheitsregel — nur EINE Instanz aktiv.
+ *
+ * Setzen/Entfernen übernimmt CanvasArea im Mount-/Cleanup-Zyklus.
+ */
+import type { CADDocument } from './CADDocument';
+
+type Listener = () => void;
+
+let activeDoc: CADDocument | null = null;
+const listeners = new Set<Listener>();
+
+/** Registriert das aktive Dokument (CanvasArea-Mount). */
+export function setActiveDocument(doc: CADDocument | null): void {
+  activeDoc = doc;
+  listeners.forEach((l) => l());
+}
+
+/** Aktives Dokument oder null (z.B. wenn Flag aus / Canvas unmounted). */
+export function getActiveDocument(): CADDocument | null {
+  return activeDoc;
+}
+
+/** Änderungsabonnement (für React-Hooks). Liefert Unsubscribe. */
+export function onActiveDocumentChanged(cb: Listener): () => void {
+  listeners.add(cb);
+  return () => listeners.delete(cb);
+}
+
+/** Bequemlichkeit: globaler Undo am aktiven Dokument. false wenn kein Doc/Stack leer. */
+export function undoActive(): boolean {
+  return activeDoc?.undo() ?? false;
+}
+
+/** Bequemlichkeit: globales Redo am aktiven Dokument. */
+export function redoActive(): boolean {
+  return activeDoc?.redo() ?? false;
+}

frontend/tests/documentService.test.ts

@@ -0,0 +1,56 @@
+/**
+ * documentService Tests (Task A4.11).
+ * Prüft Registrierung/Löschung des aktiven Dokuments und die
+ * Undo/Redo-Delegation an CADDocument.
+ */
+import { describe, it, expect, afterEach } from 'vitest';
+import { setActiveDocument, getActiveDocument, undoActive, redoActive } from '../src/kernel/document/documentService';
+import { CADDocument } from '../src/kernel/document/CADDocument';
+import { createInMemoryDoc } from './helpers/inMemoryDoc';
+import type { CADElement } from '../src/types/cad.types';
+
+function makeEl(id: string): CADElement {
+  return {
+    id,
+    type: 'rect',
+    layerId: 'l',
+    x: 0,
+    y: 0,
+    width: 1,
+    height: 1,
+    properties: {},
+  } as unknown as CADElement;
+}
+
+afterEach(() => {
+  setActiveDocument(null);
+});
+
+describe('documentService', () => {
+  it('registriert und entregistriert das aktive Dokument', () => {
+    const { ydoc } = createInMemoryDoc();
+    const doc = new CADDocument(ydoc);
+    setActiveDocument(doc);
+    expect(getActiveDocument()).toBe(doc);
+    setActiveDocument(null);
+    expect(getActiveDocument()).toBeNull();
+  });
+
+  it('undoActive delegiert an das registrierte Dokument', () => {
+    const { ydoc } = createInMemoryDoc();
+    const doc = new CADDocument(ydoc);
+    doc.addElement(makeEl('x1'));
+    setActiveDocument(doc);
+
+    expect(undoActive()).toBe(true);      // Element wird entfernt
+    expect(doc.getAllElements().length).toBe(0);
+    expect(redoActive()).toBe(true);       // wiederhergestellt
+    expect(doc.getAllElements().length).toBe(1);
+  });
+
+  it('undoActive liefert false ohne aktives Dokument', () => {
+    setActiveDocument(null);
+    expect(undoActive()).toBe(false);
+    expect(redoActive()).toBe(false);
+  });
+});