Fix: Use regex literal for wildcard route to support Express 5

server/server.js

@@ -168,7 +168,7 @@ if (fs.existsSync(clientDistPath)) {
     app.use(express.static(clientDistPath));
 
     // SPA Fallback: Any route not handled by API should return index.html
-    app.get('(.*)', (req, res) => {
+    app.get(/.*/, (req, res) => {
         if (!req.path.startsWith('/api')) {
             res.sendFile(path.join(clientDistPath, 'index.html'));
         }