feat: initial commit

frontend/src/pages/CadPreview.tsx

@@ -0,0 +1,36 @@
+import { useParams, useNavigate } from 'react-router-dom'
+import { ArrowLeft } from 'lucide-react'
+import ThreeDViewer from '../components/cad/ThreeDViewer'
+
+/**
+ * Route: /cad/:id
+ *
+ * Renders the full-screen 3D viewer for a specific CAD file.
+ * When the viewer is closed the user is navigated back.
+ */
+export default function CadPreviewPage() {
+  const { id } = useParams<{ id: string }>()
+  const navigate = useNavigate()
+
+  if (!id) {
+    return (
+      <div className="flex flex-col items-center justify-center h-full text-content-muted gap-4 p-8">
+        <p className="text-lg">No CAD file ID provided.</p>
+        <button
+          onClick={() => navigate(-1)}
+          className="flex items-center gap-2 text-sm text-accent hover:underline"
+        >
+          <ArrowLeft size={16} />
+          Go back
+        </button>
+      </div>
+    )
+  }
+
+  return (
+    <ThreeDViewer
+      cadFileId={id}
+      onClose={() => navigate(-1)}
+    />
+  )
+}