Fix upload PDF nelle card: basePath nel workerSrc di pdfjs

app/admin/page.tsx

@@ -217,8 +217,9 @@ async function pdfToImageItems(
   onProgress: (page: number, total: number) => void
 ): Promise<MediaItem[]> {
   const pdfjs = await import('pdfjs-dist');
-  // Worker file is copied to /public via the postinstall script
-  pdfjs.GlobalWorkerOptions.workerSrc = '/pdf.worker.min.mjs';
+  // Worker file is copied to /public via the postinstall script. Must include the
+  // basePath so the browser can find it when the app is mounted under /cards.
+  pdfjs.GlobalWorkerOptions.workerSrc = withBasePath('/pdf.worker.min.mjs');
 
   const arrayBuffer = await file.arrayBuffer();
   const pdf = await pdfjs.getDocument({ data: arrayBuffer }).promise;
@@ -505,7 +506,8 @@ export default function AdminDashboard() {
         }
       } catch (err) {
         console.error('Upload failed for', file.name, err);
-        showToast(`Failed to process "${file.name}".`);
+        const reason = (err as Error)?.message || 'unknown error';
+        showToast(`Failed to process "${file.name}": ${reason}. Check the browser console for details.`, 'error');
         setPdfProgress(null);
       }
     }