Calendar routes moved to events service, so blog can no
longer use url_for('blog.post.calendars...').
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Calendar templates extend post/index.html but don't provide a
post context variable. Wrap post-specific meta in an if guard
so pages without post still get basic meta from meta_base.html.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>