task(G5): browser print stylesheet - @media print A4 landscape, screen-only chrome hidden, print-area fill, print service with cleanup

frontend/src/components/LayoutBar.tsx

@@ -10,6 +10,7 @@ import React, { useCallback, useEffect, useState } from 'react';
 import type { LayoutDefinition } from '../types/cad.types';
 import { getActiveDocument, onActiveDocumentChanged } from '../kernel/document/documentService';
 import { insertTitleBlockForLayout } from '../services/titleBlockService';
+import { printLayout } from '../services/printService';
 
 export interface LayoutView {
   center: { x: number; y: number };
@@ -120,6 +121,10 @@ const LayoutBar: React.FC<LayoutBarProps> = ({ doc: docProp, bridge: bridgeProp
     reload();
   };
 
+  const handlePrint = () => {
+    void printLayout();
+  };
+
   const handleZoomTo = (l: LayoutDefinition) => {
     bridge?.zoomTo(l.viewport.center, l.viewport.scale);
   };
@@ -137,6 +142,12 @@ const LayoutBar: React.FC<LayoutBarProps> = ({ doc: docProp, bridge: bridgeProp
           onClick={handleAdd}
           disabled={!bridge || !doc}
         >+</button>
+        <button
+          type="button"
+          className="layout-bar-print screen-only"
+          title="Layout drucken (A4 landscape)"
+          onClick={handlePrint}
+        >🖨</button>
       </div>
       {layouts.length === 0 ? (
         <div className="layout-bar-empty">Keine Layouts</div>