fix: nav/footer wireframe, honeypot CSP, explore topics, comment E2E coverage

- Replace nav inline newsletter form with Subscribe CTA link per wireframe
- Remove newsletter form from footer; add Connect section with social/RSS links
- Fix honeypot inputs using hidden attribute (inline style blocked by CSP)
- Add available_tags to HomePage.get_context for Explore Topics section
- Add data-comment-form attribute to main comment form for reliable locating
- Seed approved comment in E2E content for reply flow testing
- Expand test_comments.py: moderation message, not-immediately-visible,
  missing fields, reply form visible, reply submission
- Make COMMENT_RATE_LIMIT_PER_MINUTE configurable; set 100 in dev to prevent
  E2E test exhaustion; update rate limit unit test with override_settings
- Update newsletter/home E2E tests to reflect nav form removal
- Update unit test to assert no nav/footer newsletter forms

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

config/settings/development.py

@@ -26,3 +26,5 @@ try:
     MIDDLEWARE = ["debug_toolbar.middleware.DebugToolbarMiddleware", *MIDDLEWARE]
 except Exception:
     pass
+
+COMMENT_RATE_LIMIT_PER_MINUTE = 100