fix backend bug

test-api.cjs

@@ -0,0 +1,26 @@
+const http = require('http');
+
+const data = JSON.stringify({
+  id: "default_user", height: 175, weight: 70, age: 30, gender: "male",
+  activityLevel: "light", goal: "maintain", bmi: 22.8, tdee: 2000,
+  targetCalories: 2000, targetProtein: 100, targetFat: 50, targetCarbs: 250, targetWater: 2000
+});
+
+const req = http.request({
+  hostname: 'localhost',
+  port: 3131,
+  path: '/api/profile',
+  method: 'POST',
+  headers: {
+    'Content-Type': 'application/json',
+    'Content-Length': Buffer.byteLength(data)
+  }
+}, (res) => {
+  let body = '';
+  res.on('data', chunk => body += chunk);
+  res.on('end', () => console.log('Response:', res.statusCode, body));
+});
+
+req.on('error', e => console.error('Error:', e));
+req.write(data);
+req.end();