feat: stand up E2E harness, fix a real bootstrap bug it found

Track Q Q1/Q4 (docs/PRODUCT-PLAN-v3.1-DELIVERY-PLAN.md). No E2E existed
before this. Playwright chosen - no existing test runner preference, and it
needs zero extra infra beyond the dev server this repo already has.

- playwright.config.ts, package.json e2e/e2e:ui/e2e:report scripts
- e2e/smoke.spec.ts       app boots, no console errors (network 404s from the
                          absent backend are filtered - expected, not a bug)
- e2e/currency-switch.spec.ts   Track Q Q4: switching currency must change
                          the displayed price VALUE, not just the label next
                          to it. Written specifically so the upcoming
                          checkout money-truth rewrite (frontend backlog
                          F10-F16, which replaces client-side FX math with a
                          server-computed total) has a regression net under
                          it before that rewrite starts.

The first run found a real, current bug: @marketplaces/auth ships plain tsc
output (dist/index.js), not Angular Package Format, so it carries no compiled
Ivy DI metadata. Any class-based provider from it - not just the Ed25519
Noop stub, AuthService itself hit the same failure - forces Angular to
JIT-compile at runtime, which throws immediately when @angular/compiler
isn't loaded. That breaks app bootstrap outright, for real users, not just
this test.

Fixed here with the minimum honest scope:
- src/main.ts: import '@angular/compiler' before bootstrap, so JIT works
  everywhere the package is injected, not just at one call site
- src/app/app.config.ts: useFactory instead of useClass for the Noop
  Ed25519 provider, since it has zero constructor deps and doesn't need
  Angular to derive metadata for it at all
- angular.json: raised the initial-bundle hard-error budget 1.5MB -> 1.8MB,
  because the compiler import made a correct build refuse to complete. A
  build that fails outright is worse than a bundle that's honestly larger
  than it should be.

The real fix belongs in the vitanovaPackages auth repo: publish via
ng-packagr so consumers get Ivy-compiled output and none of this is
necessary. Do not remove the compiler import until that ships - see the
comment left in main.ts.

Also fixed a genuine test defect while getting this to a real green: the
page renders duplicate .currency-option elements (desktop/mobile variants of
the same selector), so the first attempt at this test clicked into a hidden
duplicate and silently no-opped. Scoped the click to .currency-dropdown.open
and added an explicit poll for the DOM to reflect the new currency before
reading it back, rather than trusting a fixed timeout.

Verified: 3/3 E2E green, 115/115 unit tests green, arch:check clean,
production build succeeds.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

playwright.config.ts

@@ -0,0 +1,41 @@
+import { defineConfig, devices } from '@playwright/test';
+
+/**
+ * E2E harness. Track Q (docs/PRODUCT-PLAN-v3.1-DELIVERY-PLAN.md Q1) — none
+ * existed before this. Runs against the mock-data build (environment.dev's
+ * useMockData: true, per src/environments/), because the dev server this
+ * session can reach has no live backend behind it.
+ *
+ * Once a real backend is reachable, point BASE_URL at it and set
+ * PW_USE_MOCK_DATA=false to get end-to-end coverage instead of
+ * frontend-only coverage. See e2e/README.md.
+ */
+export default defineConfig({
+  testDir: './e2e',
+  fullyParallel: true,
+  forbidOnly: !!process.env.CI,
+  retries: process.env.CI ? 2 : 0,
+  workers: process.env.CI ? 2 : undefined,
+  reporter: process.env.CI ? [['github'], ['html', { open: 'never' }]] : 'list',
+
+  use: {
+    baseURL: process.env.BASE_URL ?? 'http://localhost:4200',
+    trace: 'on-first-retry',
+    screenshot: 'only-on-failure',
+  },
+
+  projects: [
+    { name: 'chromium', use: { ...devices['Desktop Chrome'] } },
+  ],
+
+  // Boots the mock-data dev server unless BASE_URL points somewhere already
+  // running (a staging box, a locally-started server).
+  webServer: process.env.BASE_URL
+    ? undefined
+    : {
+        command: 'npm run dexar',
+        url: 'http://localhost:4200',
+        reuseExistingServer: !process.env.CI,
+        timeout: 120_000,
+      },
+});