chore: generate portal-shell and portal-bff apps per ADR-0004 / ADR-0005

Add the @nx/angular, @nx/nest, @nx/vite, @nx/eslint plugins, then
generate the two apps. Adjust the empty-template tsconfig.base.json
to be Angular-compatible (drop project references and customConditions
that the empty-template defaults to but Angular doesn't support; keep
the strict-TS extensions from ADR-0004).

apps/portal-shell (Angular 21):
- standalone APIs, routing, SCSS, esbuild
- vitest-angular as unitTestRunner, playwright for e2e
- strict mode
- tags scope:portal-shell, type:app
- app.config.ts wired with provideZonelessChangeDetection() per
  ADR-0004 (Angular 21 + Nx 22 generates without zone.js by default)

apps/portal-bff (NestJS 11):
- Express adapter (default per ADR-0005)
- Jest as unitTestRunner
- tags scope:portal-bff, type:app
- main.ts wired with a global ValidationPipe configured
  whitelist + forbidNonWhitelisted + transform per ADR-0005
- Phase-2 security additions (helmet, CORS, sessions, CSRF, rate
  limit, auth guards, error filter) deferred to their respective
  ADRs - placeholder comment in main.ts

Workspace dependencies: class-validator + class-transformer added
(required by NestJS ValidationPipe at runtime). Nx-generated
.gitignore additions (.angular, __screenshots__) merged into ours.
.vscode/extensions.json and launch.json added by Nx are kept (do not
override our existing settings.json).

apps/portal-shell-e2e/playwright.config.ts

@@ -0,0 +1,68 @@
+import { defineConfig, devices } from '@playwright/test';
+import { nxE2EPreset } from '@nx/playwright/preset';
+import { workspaceRoot } from '@nx/devkit';
+
+// For CI, you may want to set BASE_URL to the deployed application.
+const baseURL = process.env['BASE_URL'] || 'http://localhost:4200';
+
+/**
+ * Read environment variables from file.
+ * https://github.com/motdotla/dotenv
+ */
+// require('dotenv').config();
+
+/**
+ * See https://playwright.dev/docs/test-configuration.
+ */
+export default defineConfig({
+  ...nxE2EPreset(__filename, { testDir: './src' }),
+  /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
+  use: {
+    baseURL,
+    /* Collect trace when retrying the failed test. See https://playwright.dev/docs/trace-viewer */
+    trace: 'on-first-retry',
+  },
+  /* Run your local dev server before starting the tests */
+  webServer: {
+    command: 'pnpm exec nx run portal-shell:serve',
+    url: 'http://localhost:4200',
+    reuseExistingServer: true,
+    cwd: workspaceRoot,
+  },
+  projects: [
+    {
+      name: 'chromium',
+      use: { ...devices['Desktop Chrome'] },
+    },
+
+    {
+      name: 'firefox',
+      use: { ...devices['Desktop Firefox'] },
+    },
+
+    {
+      name: 'webkit',
+      use: { ...devices['Desktop Safari'] },
+    },
+
+    // Uncomment for mobile browsers support
+    /* {
+      name: 'Mobile Chrome',
+      use: { ...devices['Pixel 5'] },
+    },
+    {
+      name: 'Mobile Safari',
+      use: { ...devices['iPhone 12'] },
+    }, */
+
+    // Uncomment for branded browsers
+    /* {
+      name: 'Microsoft Edge',
+      use: { ...devices['Desktop Edge'], channel: 'msedge' },
+    },
+    {
+      name: 'Google Chrome',
+      use: { ...devices['Desktop Chrome'], channel: 'chrome' },
+    } */
+  ],
+});