test(e2e): add playwright e2e stand with test pocketbase and axe checks

- playwright.config.ts: test PocketBase (port 8190) and ng serve (port 4300)
  as webServers, SIGTERM shutdown so the stand removes its temp dir
- fixtures: user via open registration, api SDK client, signedInPage with pb_auth cookie
- expectNoA11yViolations runs all axe rules (WCAG and best-practice)
- render home route on the server; main and h1 placeholder in app shell
- config tests for playwright.config.ts in test:lint; docs updated

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

playwright.config.ts

@@ -0,0 +1,35 @@
+import { defineConfig, devices } from '@playwright/test';
+import { E2E_APP_URL, E2E_PB_PORT, E2E_PB_URL } from './tests/e2e/urls';
+
+const ci = !!process.env['CI'];
+
+// Стенд e2e: временный PocketBase и `ng serve` (SSR + dev-прокси /pb) на отдельных портах.
+export default defineConfig({
+    testDir: 'tests/e2e',
+    testMatch: '**/*.e2e.ts',
+    outputDir: 'test-results',
+    retries: ci ? 1 : 0,
+    use: {
+        baseURL: E2E_APP_URL,
+        screenshot: 'only-on-failure',
+        trace: 'retain-on-failure',
+    },
+    projects: [{ name: 'chromium', use: { ...devices['Desktop Chrome'] } }],
+    webServer: [
+        {
+            command: `node tests/support/serve-test-pocketbase.ts ${E2E_PB_PORT}`,
+            url: `${E2E_PB_URL}/api/health`,
+            reuseExistingServer: !ci,
+            // По умолчанию Playwright шлёт SIGKILL: стенд не успел бы удалить временную папку.
+            // Таймаут больше STOP_TIMEOUT_MS стенда (5 с), чтобы он успел добить PocketBase и убрать папку.
+            gracefulShutdown: { signal: 'SIGTERM', timeout: 10_000 },
+        },
+        {
+            command: `pnpm ng serve --port ${new URL(E2E_APP_URL).port}`,
+            url: E2E_APP_URL,
+            env: { PB_URL: E2E_PB_URL },
+            reuseExistingServer: !ci,
+            timeout: 180_000,
+        },
+    ],
+});