chore(07-01): install @playwright/test@1.60.0, add test:e2e scripts

- Add @playwright/test@1.60.0 to apps/pwa devDependencies (pinned, not floated)
- Install WebKit and Chromium browser engines via playwright install
- Add test:e2e, test:e2e:ui, test:e2e:headed scripts to apps/pwa/package.json
- Add root workspace test:e2e delegate script to package.json

package.json

@@ -7,6 +7,7 @@
     "dev:pwa": "pnpm --filter @familysync/pwa dev",
     "build": "pnpm --filter @familysync/api build && pnpm --filter @familysync/pwa build",
     "test": "pnpm --filter @familysync/api test",
+    "test:e2e": "pnpm --filter @familysync/pwa test:e2e",
     "lint": "pnpm -r lint",
     "typecheck": "pnpm -r typecheck"
   }