task(A4.14): make v2 tool path the default (verified e2e without flag)

frontend/src/App.tsx

@@ -19,6 +19,7 @@ import MobileDrawers from './components/MobileDrawers';
 import BackgroundImport from './components/BackgroundImport';
 import HistoryPanel from './components/HistoryPanel';
 import V2HistoryPanel from './components/V2HistoryPanel';
+import { V2_TOOLS_ENABLED } from './kernel/featureFlags';
 import SettingsModal from './components/SettingsModal';
 import InlineTextEditor from './components/InlineTextEditor';
 import { BackgroundService, type BackgroundConfig } from './services/backgroundService';
@@ -1574,7 +1575,7 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
         onTabChange={setActiveRibbonTab}
         onAction={handleRibbonAction}
         onIsV2ToolActive={(toolId: string) =>
-          import.meta.env.VITE_TOOL_DISPATCHER === 'v2' &&
+          V2_TOOLS_ENABLED &&
           activeTool === toolId &&
           !!pluginRegistry.getToolV2(toolId)
         }
@@ -1743,7 +1744,7 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
         onApply={handleBgApply}
         backgroundService={bgServiceRef.current}
       />
-      {historyPanelOpen && (import.meta.env.VITE_TOOL_DISPATCHER === 'v2' ? (
+      {historyPanelOpen && (V2_TOOLS_ENABLED ? (
         <V2HistoryPanel
           onClose={() => setHistoryPanelOpen(false)}
         />

frontend/src/components/CanvasArea.tsx

@@ -17,6 +17,7 @@ import { logger } from '../utils/logger';
 import { CADDocument } from '../kernel/document/CADDocument';
 import { YjsDocument } from '../crdt/YjsDocument';
 import { setActiveDocument, getActiveDocument } from '../kernel/document/documentService';
+import { V2_TOOLS_ENABLED } from '../kernel/featureFlags';
 import { pluginRegistry } from '../plugins';
 
 const CanvasArea: React.FC<CanvasAreaProps> = ({
@@ -53,10 +54,9 @@ const CanvasArea: React.FC<CanvasAreaProps> = ({
       canvas, zoomPan, renderEngine, snapEngine, selectionEngine, spatialIndex, layerManager,
     );
 
-    // ── Task A2/A4: V2-Tool-Dispatcher hinter Feature-Flag ──
-    // Flag VITE_TOOL_DISPATCHER=v2: aktiviert den InteractionDispatcher UND
-    // verdrahtet ihn mit einem lokalen CADDocument + SelectionBridge (Task A4.1).
-    if (import.meta.env.VITE_TOOL_DISPATCHER === 'v2') {
+    // ── Task A2/A4.14: V2-Pfad ist seit Verifikation STANDARD — Opt-out via
+    // VITE_TOOL_DISPATCHER=legacy. Siehe kernel/featureFlags.ts.
+    if (V2_TOOLS_ENABLED) {
       const ydoc = new YjsDocument();
       ydoc.data.layers.set('layer-0', {
         id: 'layer-0', name: 'Standard', visible: true, locked: false,

frontend/src/components/RibbonBar.tsx

@@ -1,6 +1,7 @@
 import React from 'react';
 import type { RibbonBarProps, RibbonTab } from '../types/ui.types';
 import { pluginRegistry } from '../plugins';
+import { V2_TOOLS_ENABLED } from '../kernel/featureFlags';
 
 const tabs: Array<{ id: RibbonTab; label: string; svg: React.ReactNode }> = [
   { id: 'start', label: 'Start', svg: <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round"><path d="m3 9 9-7 9 7v11a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2z"/><polyline points="9 22 9 12 15 12 15 22"/></svg> },
@@ -38,8 +39,8 @@ const RibbonBar: React.FC<RibbonBarProps> = ({
       </div>
 
       <div className="ribbon-content" id="ribbon-content">
-        {/* ===== V2 TOOLS (Task A4.13, nur bei aktivem Dispatcher-Flag) ===== */}
-        {activeTab === 'canvas' && import.meta.env.VITE_TOOL_DISPATCHER === 'v2' && (
+        {/* ===== V2 TOOLS (Task A4.13/A4.14: Standard aktiv — Opt-out via VITE_TOOL_DISPATCHER=legacy) ===== */}
+        {activeTab === 'canvas' && V2_TOOLS_ENABLED && (
           <div style={{
             display: 'flex', flexWrap: 'wrap', gap: '6px', alignItems: 'center',
             padding: '8px 4px', width: '100%',
@@ -51,6 +52,7 @@ const RibbonBar: React.FC<RibbonBarProps> = ({
               return (
                 <button
                   key={tool.manifest.id}
+                  data-v2tool={tool.manifest.id}
                   title={tool.manifest.description ?? tool.manifest.label}
                   onClick={() => onAction(`v2tool:${tool.manifest.id}`)}
                   style={{

frontend/src/kernel/featureFlags.ts

@@ -0,0 +1,15 @@
+/**
+ * featureFlags – Zentrale Feature-Schalter (Task A4.14).
+ *
+ * V2_TOOLS_ENABLED: Ab v2.0 ist der Plugin-first-Pfad (InteractionDispatcher,
+ * CADDocument, dynamisches Ribbon, V2HistoryPanel) STANDARDMÄSSIG AKTIV.
+ * Opt-out für den Legacy-Pfad: VITE_TOOL_DISPATCHER=legacy setzen.
+ *
+ * Begründung Historie: Vor A4.14 war V2 opt-in ('v2' explizit nötig), weil
+ * noch keine Browser-Verifikation existierte. Die Playwright-Verifikation
+ * (phase-a-verify.test.ts, grün) hat das Risiko entwertet.
+ */
+
+/** Ist der V2-Werkzeugpfad (Dispatcher/CADDocument) aktiv? Default: ja. */
+export const V2_TOOLS_ENABLED: boolean =
+  import.meta.env.VITE_TOOL_DISPATCHER !== 'legacy';