Add global JSON error handler

server.js

@@ -466,6 +466,15 @@ app.get("/api/status", (req, res) => {
   });
 });
 
+// Global error handler
+app.use((err, req, res, next) => {
+  console.error("Unhandled error:", err);
+  res.status(500).json({
+    error: "Internal Server Error",
+    message: err.message
+  });
+});
+
 const PORT = process.env.PORT || 3000;
 app.listen(PORT, () => {
   console.log(`GLB Generation Engine running on http://localhost:${PORT}`);