fix dropbox load fallback

src/App.tsx

@@ -1,6 +1,7 @@
 import React, { useState, useMemo, useEffect } from 'react';
 import * as XLSX from 'xlsx';
 import { X } from 'lucide-react';
+import defaultWorkbookUrl from '../data (3).xlsx?url';
 import { cn } from './lib/utils';
 import { AppState, ExcelRow, resolveColumnIndices, COLUMNS } from './types';
 import { ColumnsProvider } from './contexts/ColumnsContext';
@@ -85,6 +86,31 @@ function readStoredBcSyncQueue(): BcSyncQueue {
   }
 }
 
+async function loadWorkbookFromUrl(url: string) {
+  const response = await fetch(url, { cache: 'no-store' });
+  if (!response.ok) {
+    throw new Error(`HTTP ${response.status}`);
+  }
+
+  const arrayBuffer = await response.arrayBuffer();
+  if (arrayBuffer.byteLength < 100) {
+    throw new Error('File too small');
+  }
+
+  const wb = XLSX.read(arrayBuffer, { type: 'array' });
+  const wsname = wb.SheetNames[0];
+  const ws = wb.Sheets[wsname];
+  const allData = XLSX.utils.sheet_to_json<any[]>(ws, { header: 1 });
+  const rows = allData.slice(1);
+  const headers = allData.slice(0, 1)[0] || [];
+
+  return {
+    headers,
+    rows,
+    fileMeta: { rev: url, size: arrayBuffer.byteLength },
+  };
+}
+
 export default function App() {
   const [session, setSession] = useState<AuthSession | null>(() => getStoredSession());
 
@@ -201,13 +227,15 @@ export default function App() {
           const cacheBuster = `t_${Date.now()}`;
           const fileUrl = `/dropbox-file/scl/fi/usa8me7ywgylrij2bt6hj/Data-Matrix.xlsx?rlkey=tsec8csrhye54u1fdvk15ped1&dl=1&${cacheBuster}=${Date.now()}`;
           console.log('Fetching Data-Matrix.xlsx from Dropbox (hard refresh)...');
+          try {
             const response = await fetch(fileUrl, { cache: 'no-store' });
             if (!response.ok) throw new Error(`HTTP ${response.status}`);
 
             const contentType = response.headers.get('content-type');
             if (contentType && contentType.includes('text/html')) {
-            throw new Error('Dropbox returned an HTML page instead of the Excel file. This usually means the sharing link has expired or requires manual interaction. Please generate a new "Copy Link" from Dropbox.');
+              throw new Error('Dropbox returned an HTML page instead of the Excel file.');
             }
+
             const arrayBuffer = await response.arrayBuffer();
             if (arrayBuffer.byteLength < 100) throw new Error('File too small');
 
@@ -217,6 +245,13 @@ export default function App() {
             allData = XLSX.utils.sheet_to_json<any[]>(ws, { header: 1 });
             rows = allData.slice(1);
             fileMeta = { rev: 'dev', size: arrayBuffer.byteLength };
+          } catch (devErr) {
+            console.warn('Dropbox dev load failed, using bundled workbook fallback:', devErr);
+            const fallback = await loadWorkbookFromUrl(defaultWorkbookUrl);
+            allData = [fallback.headers, ...fallback.rows];
+            rows = fallback.rows;
+            fileMeta = fallback.fileMeta;
+          }
         } else {
           console.log('Fetching file info from Dropbox...');
           const infoRes = await fetch('/api/dropbox-proxy?info=1');
@@ -226,8 +261,15 @@ export default function App() {
           }
           
           console.log('Fetching Data-Matrix.xlsx from proxy (hard refresh)...');
+          try {
             const response = await fetch('/api/dropbox-proxy', { cache: 'no-store' });
             if (!response.ok) throw new Error(`HTTP ${response.status}`);
+
+            const contentType = response.headers.get('content-type');
+            if (contentType && contentType.includes('text/html')) {
+              throw new Error('Dropbox returned an HTML page instead of the Excel file.');
+            }
+
             const arrayBuffer = await response.arrayBuffer();
             if (arrayBuffer.byteLength < 100) throw new Error('File too small');
 
@@ -236,6 +278,13 @@ export default function App() {
             const ws = wb.Sheets[wsname];
             allData = XLSX.utils.sheet_to_json<any[]>(ws, { header: 1 });
             rows = allData.slice(1);
+          } catch (prodErr) {
+            console.warn('Dropbox prod load failed, using bundled workbook fallback:', prodErr);
+            const fallback = await loadWorkbookFromUrl(defaultWorkbookUrl);
+            allData = [fallback.headers, ...fallback.rows];
+            rows = fallback.rows;
+            fileMeta = fallback.fileMeta;
+          }
         }
 
         if (rows.length > 0) {