Fix Express 5 wildcard routing in SPA fallback

server/index.js

@@ -199,7 +199,7 @@ if (fs.existsSync(distPath)) {
   app.use(express.static(distPath));
 
   // SPA Fallback: serve index.html for unknown routes
-  app.get('*', (req, res) => {
+  app.use((req, res) => {
     if (req.path.startsWith('/api') || req.path.startsWith('/uploads')) {
       return res.status(404).json({ error: 'Not found' });
     }