feat(k8s): add HelmService and rewrite deleteApplication

- New HelmService wrapping Helm CLI (install/upgrade, rollback, uninstall, history, status)
- deleteApplication: helm uninstall + explicit cleanup of kept PVCs, secrets, TLS certs
- buildHelmValues: include registry.url for pull secret
- Add scaleDeployment for lifecycle suspend/resume
- Unit tests for buildHelmValues and HelmService

backend/src/kubernetes/helm.service.spec.ts

@@ -0,0 +1,86 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { HelmService } from './helm.service';
+import * as fs from 'fs';
+import * as path from 'path';
+
+describe('HelmService', () => {
+  let service: HelmService;
+  let writeSpy: jest.SpyInstance;
+
+  beforeEach(async () => {
+    jest.clearAllMocks();
+    writeSpy = jest.spyOn(fs.promises, 'writeFile').mockResolvedValue(undefined);
+
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [HelmService],
+    }).compile();
+
+    service = module.get<HelmService>(HelmService);
+  });
+
+  afterEach(() => {
+    writeSpy.mockRestore();
+  });
+
+  it('should be defined', () => {
+    expect(service).toBeDefined();
+  });
+
+  describe('chartPath', () => {
+    it('should resolve to helm/cloudhost-app relative to project root', () => {
+      const expectedSuffix = path.join('helm', 'cloudhost-app');
+      expect((service as any).chartPath).toContain(expectedSuffix);
+    });
+  });
+
+  describe('writeTempKubeconfig', () => {
+    it('should write kubeconfig with mode 0o600', async () => {
+      const result = await (service as any).writeTempKubeconfig('apiVersion: v1\nclusters: []');
+      expect(writeSpy).toHaveBeenCalledWith(
+        expect.stringContaining('cloudhost-kube-'),
+        'apiVersion: v1\nclusters: []',
+        { mode: 0o600 },
+      );
+      expect(typeof result).toBe('string');
+    });
+  });
+
+  describe('writeTempValues', () => {
+    it('should write values as JSON with mode 0o600', async () => {
+      const values = { app: { name: 'test' } };
+      const result = await (service as any).writeTempValues(values);
+      expect(writeSpy).toHaveBeenCalledWith(
+        expect.stringContaining('cloudhost-vals-'),
+        JSON.stringify(values, null, 2),
+        { mode: 0o600 },
+      );
+      expect(result).toContain('.json');
+    });
+  });
+
+  describe('cleanupTempFiles', () => {
+    it('should not throw if no files provided', () => {
+      expect(() => (service as any).cleanupTempFiles()).not.toThrow();
+    });
+  });
+
+  describe('history - parsing', () => {
+    it('should map app_version to appVersion', () => {
+      const raw = [
+        { revision: 1, updated: '2024-01-01', status: 'deployed', chart: 'cloudhost-app-0.1.0', app_version: '1.0.0', description: 'Install complete' },
+        { revision: 2, updated: '2024-01-02', status: 'superseded', chart: 'cloudhost-app-0.1.0', app_version: '1.0.0', description: 'Upgrade complete' },
+      ];
+      const mapped = raw.map((r) => ({
+        revision: r.revision,
+        updated: r.updated,
+        status: r.status,
+        chart: r.chart,
+        appVersion: r.app_version,
+        description: r.description,
+      }));
+      expect(mapped[0].appVersion).toBe('1.0.0');
+      expect(mapped[1].revision).toBe(2);
+      expect(mapped).toHaveLength(2);
+    });
+  });
+});