Address PR review feedback

- Gate e2e-admin superuser behind E2E_MODE env var (security)
- Add status and tag filters to ArticleFilterSet
- Set default_ordering to -published_date on listing viewset
- Add summary to ArticlePage.search_fields for search support
- Add 4 new tests for filters, ordering, and search fields

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docker-compose.yml

@@ -24,6 +24,7 @@ services:
       EMAIL_BACKEND: django.core.mail.backends.console.EmailBackend
       DEFAULT_FROM_EMAIL: hello@nohypeai.com
       NEWSLETTER_PROVIDER: buttondown
+      E2E_MODE: "1"
     depends_on:
       db:
         condition: service_healthy