system.pages.expires was 604800 (Grav default), so browsers cached feed HTML and
entry media for a week with no revalidation — deleted entries lingered as ghost
cards (images 404), and edited/new photos didn't appear until a hard refresh. Set
expires: 0 → Cache-Control: no-cache, must-revalidate. With etag already on, an
unchanged page returns a cheap 304; changed content shows immediately. Also fixes
reorder staleness (photo-N.jpg is reused across reorders at the same URL). The
server-side page cache (cache.enabled) is untouched.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>