add admin endpoint to retrieve full session list for dashboard

server.js

@@ -126,6 +126,12 @@ app.get('/api/leaderboard', (req, res) => {
   res.json(sorted);
 });
 
+// GET /api/admin/sessions — full session list for the admin dashboard (admin only)
+app.get('/api/admin/sessions', adminAuth, (req, res) => {
+  const { sessions } = readData();
+  res.json([...sessions].sort((a, b) => new Date(b.timestamp) - new Date(a.timestamp)));
+});
+
 // GET /api/export — download full raw data (admin only)
 app.get('/api/export', adminAuth, (req, res) => {
   res.setHeader('Content-Disposition', 'attachment; filename="2afc_data.json"');