task(A4.13): dynamic v2 tool section in ribbon behind flag

frontend/src/App.tsx

@@ -1148,6 +1148,15 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
     if (action === 'measure') { setActiveTool('dimension'); setCommandHistory((prev) => [...prev, { prefix: '·', text: 'Messwerkzeug aktiv', type: 'info' }]); return; }
     if (action === 'history') { setHistoryPanelOpen((prev) => !prev); return; }
 
+    // ─── V2 tools (Task A4.13): 'v2tool:<id>' → aktives Tool umschalten. Der
+    // bestehende CanvasArea-Sync aus A4.1 routet es an den Dispatcher (Flag aktiv).
+    if (action.startsWith('v2tool:')) {
+      const toolId = action.slice('v2tool:'.length);
+      setActiveTool(toolId);
+      setCommandHistory((prev) => [...prev, { prefix: '·', text: `V2-Werkzeug aktiv: ${toolId}`, type: 'info' }]);
+      return;
+    }
+
     // ─── Background ───
     if (action === 'background-import') { setBgImportOpen(true); return; }
 
@@ -1564,6 +1573,11 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
         activeTab={activeRibbonTab}
         onTabChange={setActiveRibbonTab}
         onAction={handleRibbonAction}
+        onIsV2ToolActive={(toolId: string) =>
+          import.meta.env.VITE_TOOL_DISPATCHER === 'v2' &&
+          activeTool === toolId &&
+          !!pluginRegistry.getToolV2(toolId)
+        }
         canvasBgColor={canvasBgColor}
         gridColor={gridColor}
         rulerEnabled={rulerEnabled}