fix: use fileURLToPath for dirname resolution (#289)

backend/server.js

@@ -1,9 +1,11 @@
 import path from 'path';
+import { fileURLToPath } from 'url';
 import express from 'express';
 import cors from 'cors';
 import RateLimit from 'express-rate-limit';
 import { Sequelize } from 'sequelize';
-const __dirname = path.dirname(new URL(import.meta.url).pathname);
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
 const app = express();
 
 // enable frontend access