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>

package.json

@@ -10,6 +10,7 @@
         "test:lint": "tsc -p tsconfig.tests.json && vitest run --config vitest.lint.config.mts",
         "test:api": "pnpm test:lint && vitest run --config vitest.api.config.mts",
         "test:integration": "pnpm test:lint && ng run pchelpcrm:test-integration",
+        "e2e": "pnpm test:lint && playwright test",
         "lint": "eslint .",
         "lint:fix": "eslint . --fix",
         "serve:ssr:pchelpcrm": "node dist/pchelpcrm/server/server.mjs",
@@ -36,7 +37,9 @@
         "@angular/build": "^22.2.3",
         "@angular/cli": "^22.2.3",
         "@angular/compiler-cli": "^22.2.0",
+        "@axe-core/playwright": "^4.14.0",
         "@eslint/js": "^10.0.1",
+        "@playwright/test": "^1.64.1",
         "@types/express": "^5.0.1",
         "@types/node": "^22.12.0",
         "angular-eslint": "^22.6.0",