The logo, favicons and app icons are served from public/img under fixed
names with a browser cache of hours, and the service worker fetches them
through that cache. After the mark changed on 2026-09-27, returning
visitors kept the old cat until their copies expired, and the favicon
and an installed app's icon hold on longer still.
Every URL that names one now carries ?v=BRAND_V (src/lib/brand.ts,
brandImage()): the header, sign-in, About, the mail empty state, the
notification icons, index.html's favicon links, the manifest's icons
and the service worker's shell and notification icons. Date-stamped,
never a counter, for the sites' ASSET_V reason; the three static files
carry the value written out, and the comment says to keep them in step.
jcoffey-dev