Add root env loading and registration config

backend/src/config/jwt.js

@@ -1,7 +1,13 @@
 import { config } from 'dotenv'
+import { fileURLToPath } from 'url'
+import { dirname, resolve } from 'path'
 
-// Load environment variables
-config()
+// Load environment variables from root directory
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = dirname(__filename)
+const rootDir = resolve(__dirname, '../../..')
+
+config({ path: resolve(rootDir, '.env') })
 
 export const jwtConfig = {
   secret: process.env.JWT_SECRET || 'fallback-secret-for-development',