Fix: Use regex for catch-all route to ensure Express 5 compatibility

backend/server.js

@@ -133,9 +133,8 @@ app.get('/sentinel', (req, res) => res.sendFile(path.join(__dirname, 'public', '
 app.get('/manifesto', (req, res) => res.sendFile(path.join(__dirname, 'public', 'manifesto.html')));
 app.get('/broadcast', (req, res) => res.sendFile(path.join(__dirname, 'public', 'broadcast.html')));
 
-// Catch-all for React/Frontend routes should come AFTER specific API/Static routes
-app.get('/:path*', (req, res, next) => {
-  if (req.path.startsWith('/api')) return next();
+// Catch-all for React/Frontend routes
+app.get(/^(?!\/api).+/, (req, res) => {
   res.sendFile(path.join(__dirname, 'public', 'index.html'));
 });