test(contract): add center-guild registration contract integration test

Fabric.Backend.Center/src/health.integration.spec.ts

@@ -2,13 +2,14 @@ import { INestApplication } from '@nestjs/common';
 import { Test } from '@nestjs/testing';
 import request from 'supertest';
 import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+import { createHmac, randomUUID } from 'crypto';
 
 process.env.DB_HOST = '127.0.0.1';
 process.env.DB_PORT = '3307';
 process.env.DB_USER = 'fabric';
 process.env.DB_PASSWORD = 'fabric';
 process.env.DB_NAME = 'fabric_center';
-process.env.DB_SYNC = 'false';
+process.env.DB_SYNC = 'true';
 process.env.CENTER_SHARED_SECRET = 'test-center-secret';
 process.env.JWT_ACCESS_SECRET = 'test-access-secret';
 process.env.JWT_REFRESH_SECRET = 'test-refresh-secret';
@@ -37,4 +38,32 @@ describe('center integration (mysql + api)', () => {
     expect(res.body.ok).toBe(true);
     expect(res.body.database).toBe('ready');
   });
+
+  it('POST /api/nodes/register follows center-guild contract (version + hmac)', async () => {
+    const body = {
+      nodeId: `guild-node-${Date.now()}`,
+      name: 'Guild Node Contract Test',
+      endpoint: `http://guild-${Date.now()}:7002`,
+    };
+
+    const timestamp = new Date().toISOString();
+    const nonce = randomUUID();
+    const canonical = ['POST', '/api/nodes/register', timestamp, nonce, JSON.stringify(body)].join('\n');
+    const signature = createHmac('sha256', process.env.CENTER_SHARED_SECRET as string)
+      .update(canonical)
+      .digest('hex');
+
+    const res = await request(app.getHttpServer())
+      .post('/api/nodes/register')
+      .set('x-fabric-version', '1')
+      .set('x-fabric-timestamp', timestamp)
+      .set('x-fabric-nonce', nonce)
+      .set('x-fabric-signature', signature)
+      .send(body);
+
+    expect(res.status).toBe(201);
+    expect(res.body.status).toBe('accepted');
+    expect(res.body.negotiatedVersion).toBe('1');
+    expect(res.body.node.nodeId).toBe(body.nodeId);
+  });
 });