refactor: Introduce dedicated Document and Asset types and migrate codebase from DocumentLike.

frontend/src/preview/DocumentViewerLayout.tsx

@@ -5,14 +5,7 @@ import { DownloadIcon } from '../ui/icons';
 import PdfViewer from './PdfViewer';
 import { AUDIO_EXTENSIONS, VIDEO_EXTENSIONS } from '../constants/preview';
 
-interface DocumentLike {
-  id?: string;
-  title?: string;
-  mime_type?: string;
-  filename?: string;
-  original_name?: string;
-  [key: string]: unknown;
-}
+import type { Document } from '../types/documents';
 
 interface DocumentLink {
   url?: string;
@@ -36,7 +29,7 @@ interface ContentTabConfig {
 type LayoutMode = 'split' | 'stacked' | (string & {});
 
 interface DocumentViewerLayoutProps {
-  document?: DocumentLike | null;
+  document?: Document | null;
   documentLink?: DocumentLink | null;
   summaryProps?: Record<string, unknown>;
   metadataPayload?: unknown;