fix(ci): fix integration test collection and skip Playwright in CI

- Add @pytest.mark.oauth to OAuth-dependent tests in
  test_scope_authorization.py so they're excluded from single-user job
- Add module-level pytestmark to test_introspection_authorization.py
- Fix single-user marker expression to also exclude oauth smoke tests
- Add --ignore paths for multi-user, qdrant, and RAG evaluation tests
- Uncomment GITHUB_ACTIONS skip in oauth_callback_server fixture
- Add GITHUB_ACTIONS skip to login_flow_oauth_token fixture
- Mount third_party/oidc volume in docker-compose.yml app service
- Add OIDC diagnostic step in CI for playwright jobs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -35,7 +35,9 @@ services:
       - ./app-hooks:/docker-entrypoint-hooks.d:ro
       # Mount OIDC development directory outside /var/www/html to avoid rsync conflicts
       # The post-installation hook will register /opt/apps as an additional app directory
-      - ./third_party:/opt/apps:ro
+      #- ./third_party:/opt/apps:ro
+      - ./third_party/astrolabe:/opt/apps/astrolabe:ro
+      - ./third_party/oidc:/opt/apps/oidc:ro
     environment:
       - NEXTCLOUD_TRUSTED_DOMAINS=app
       - NEXTCLOUD_ADMIN_USER=admin