test: convert phase-06-tests.js from Jest to Node.js native test runner

Replace describe/before/it/expect() (Jest) with the node:test module
and node:assert. All test logic, endpoints, and assertion semantics are
preserved; the file now runs with: node --test backend/test/phase-06-tests.js

Co-Authored-By: claude-flow <ruv@ruv.net>

backend/test/phase-06-tests.js

@@ -1,3 +1,5 @@
+const { test, describe, before } = require('node:test');
+const assert = require('node:assert');
 const request = require('supertest');
 const app = require('../src/index.js');
 const { Pool } = require('pg');
@@ -29,49 +31,49 @@ describe('Phase 06 - Recovery Tracking & Swap System', () => {
   });
 
   describe('06-02: Muscle Group Recovery Tracking', () => {
-    it('GET /api/recovery/muscle-groups - should return recovery status', async () => {
+    test('GET /api/recovery/muscle-groups - should return recovery status', async () => {
       const res = await request(app)
         .get('/api/recovery/muscle-groups')
         .set('Authorization', `Bearer ${authToken}`);
 
-      expect(res.status).toBe(200);
+      assert.strictEqual(res.status, 200);
-      expect(res.body).toHaveProperty('userId');
+      assert.ok('userId' in res.body, 'response should have userId');
-      expect(res.body).toHaveProperty('muscleGroups');
+      assert.ok('muscleGroups' in res.body, 'response should have muscleGroups');
-      expect(Array.isArray(res.body.muscleGroups)).toBe(true);
+      assert.ok(Array.isArray(res.body.muscleGroups), 'muscleGroups should be an array');
     });
 
-    it('GET /api/recovery/most-recovered - should return top recovered groups', async () => {
+    test('GET /api/recovery/most-recovered - should return top recovered groups', async () => {
       const res = await request(app)
         .get('/api/recovery/most-recovered?limit=3')
         .set('Authorization', `Bearer ${authToken}`);
 
-      expect(res.status).toBe(200);
+      assert.strictEqual(res.status, 200);
-      expect(res.body).toHaveProperty('recovered');
+      assert.ok('recovered' in res.body, 'response should have recovered');
-      expect(res.body.limit).toBe(3);
+      assert.strictEqual(res.body.limit, 3);
     });
   });
 
   describe('06-03: Smart Workout Recommendations', () => {
-    it('GET /api/recommendations/smart-workout - should return recommendations', async () => {
+    test('GET /api/recommendations/smart-workout - should return recommendations', async () => {
       const res = await request(app)
         .get('/api/recommendations/smart-workout')
         .set('Authorization', `Bearer ${authToken}`);
 
-      expect(res.status).toBe(200);
+      assert.strictEqual(res.status, 200);
-      expect(res.body).toHaveProperty('recommendations');
+      assert.ok('recommendations' in res.body, 'response should have recommendations');
-      expect(Array.isArray(res.body.recommendations)).toBe(true);
+      assert.ok(Array.isArray(res.body.recommendations), 'recommendations should be an array');
     });
   });
 
   describe('06-01: Workout Swap System', () => {
-    it('GET /api/workouts/available - should return available exercises', async () => {
+    test('GET /api/workouts/available - should return available exercises', async () => {
       const res = await request(app)
         .get('/api/workouts/available')
         .set('Authorization', `Bearer ${authToken}`);
 
-      expect(res.status).toBe(200);
+      assert.strictEqual(res.status, 200);
-      expect(res.body).toHaveProperty('exercises');
+      assert.ok('exercises' in res.body, 'response should have exercises');
-      expect(Array.isArray(res.body.exercises)).toBe(true);
+      assert.ok(Array.isArray(res.body.exercises), 'exercises should be an array');
     });
   });
 });