The cache namespace was the help center slug, so a rename or delete stranded
the old namespace and kept serving those pages. It is a fixed namespace now,
which also drops a query per admin write.
Headers are set by the cache wrapper instead of the handlers, because the cache
restores only the body and content type. Search results and .md articles were
losing their noindex on every hit. Also cut the TTL to 5 minutes and clear on
agent writes, so a deleted avatar does not leave a broken image on an article.
Geist replaces Instrument Sans and is served from static/ instead of Google
Fonts, so it works on installs with no internet access.
Public help center pages are cached in Redis via fastcache with ETags, and any
admin write clears the group so edits show up on the next load.
Abhinav Raut