feat: add Prisma schema and PrismaService with integration tests (postgres on :5433)

apps/api/src/prisma/prisma.service.spec.ts

@@ -0,0 +1,39 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { PrismaService } from './prisma.service';
+
+describe('PrismaService', () => {
+  let prisma: PrismaService;
+
+  beforeAll(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [PrismaService],
+    }).compile();
+    prisma = module.get<PrismaService>(PrismaService);
+    await prisma.onModuleInit();
+  });
+
+  afterAll(async () => {
+    await prisma.onModuleDestroy();
+  });
+
+  it('connects to postgres', async () => {
+    const result = await prisma.$queryRaw<[{ ok: bigint }]>`SELECT 1 AS ok`;
+    expect(Number(result[0]!.ok)).toBe(1);
+  });
+
+  it('creates and retrieves a Group, then cleans up', async () => {
+    const group = await prisma.group.create({
+      data: {
+        platform: 'whatsapp',
+        platformId: `test-group-${Date.now()}@g.us`,
+        name: 'Test Group',
+      },
+    });
+
+    expect(group.id).toBeDefined();
+    expect(group.platform).toBe('whatsapp');
+    expect(group.isActive).toBe(true);
+
+    await prisma.group.delete({ where: { id: group.id } });
+  });
+});