fix(13-03): dynamic import PreviewModal to prevent SSR DOMMatrix crash

react-pdf calls new DOMMatrix() at module level — static import causes
500 on document page during SSR. Same pattern as PdfViewer/PdfViewerWrapper.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

teressa-copeland-homes/src/app/portal/(protected)/documents/[docId]/_components/PreparePanel.tsx

@@ -1,7 +1,11 @@
 'use client';
 import { useState, useEffect } from 'react';
 import { useRouter } from 'next/navigation';
-import { PreviewModal } from './PreviewModal';
+import dynamic from 'next/dynamic';
+
+// PreviewModal imports react-pdf which calls new DOMMatrix() at module level —
+// must be loaded client-only to avoid SSR crash, same pattern as PdfViewer.
+const PreviewModal = dynamic(() => import('./PreviewModal').then(m => m.PreviewModal), { ssr: false });
 
 interface PreparePanelProps {
   docId: string;