Fix authenticated media flows and upload preflight handling

frontend/src/App.tsx

@@ -14,6 +14,7 @@ import SettingsScreen from './components/SettingsScreen';
 import UploadSurface from './components/UploadSurface';
 import {
   clearProcessingLogs,
+  downloadBlobFile,
   deleteDocument,
   exportContentsMarkdown,
   getAppSettings,
@@ -117,15 +118,6 @@ export default function App(): JSX.Element {
     }
   }, []);
 
-  const downloadBlob = useCallback((blob: Blob, filename: string): void => {
-    const objectUrl = URL.createObjectURL(blob);
-    const anchor = document.createElement('a');
-    anchor.href = objectUrl;
-    anchor.download = filename;
-    anchor.click();
-    URL.revokeObjectURL(objectUrl);
-  }, []);
-
   const loadCatalogs = useCallback(async (): Promise<void> => {
     const [tags, paths, types] = await Promise.all([listTags(true), listPaths(true), listTypes(true)]);
     setKnownTags(tags);
@@ -465,13 +457,13 @@ export default function App(): JSX.Element {
         only_trashed: documentView === 'trash',
         include_trashed: false,
       });
-      downloadBlob(result.blob, result.filename);
+      downloadBlobFile(result.blob, result.filename);
     } catch (caughtError) {
       setError(caughtError instanceof Error ? caughtError.message : 'Failed to export selected markdown files');
     } finally {
       setIsRunningBulkAction(false);
     }
-  }, [documentView, downloadBlob, selectedDocumentIds]);
+  }, [documentView, selectedDocumentIds]);
 
   const handleExportPath = useCallback(async (): Promise<void> => {
     const trimmedPrefix = exportPathInput.trim();
@@ -487,13 +479,13 @@ export default function App(): JSX.Element {
         only_trashed: documentView === 'trash',
         include_trashed: false,
       });
-      downloadBlob(result.blob, result.filename);
+      downloadBlobFile(result.blob, result.filename);
     } catch (caughtError) {
       setError(caughtError instanceof Error ? caughtError.message : 'Failed to export path markdown files');
     } finally {
       setIsRunningBulkAction(false);
     }
-  }, [documentView, downloadBlob, exportPathInput]);
+  }, [documentView, exportPathInput]);
 
   const handleSaveSettings = useCallback(async (payload: AppSettingsUpdate): Promise<void> => {
     setIsSavingSettings(true);