test(10-02): add seed registration coverage for tender-radar (CONFIG-01)

- asserts seedModule called once with slug 'tender-radar', isSystem: true,
  and a bilingual (de/en) description object

apps/api/src/tenders/tenders.seed.spec.ts

@@ -0,0 +1,18 @@
+import { describe, expect, it, vi } from 'vitest';
+import { seedTendersModule } from './tenders.seed';
+
+describe('seedTendersModule', () => {
+  it('calls moduleRegistryService.seedModule once with tender-radar slug', async () => {
+    const mockSeedModule = vi.fn().mockResolvedValue(undefined);
+    const mockModuleRegistryService = { seedModule: mockSeedModule } as any;
+
+    await seedTendersModule(mockModuleRegistryService);
+
+    expect(mockSeedModule).toHaveBeenCalledTimes(1);
+    const arg = mockSeedModule.mock.calls[0][0];
+    expect(arg.slug).toBe('tender-radar');
+    expect(arg.isSystem).toBe(true);
+    expect(arg.description).toHaveProperty('de');
+    expect(arg.description).toHaveProperty('en');
+  });
+});