The photo endpoint was cached for five minutes with no revalidation, and only
the settings page added a version to the URL, so the header, the message list
and the reader kept the old photo until it expired.
- every <Avatar> reads a per-address version (and refetches when it changes);
saving or removing a photo bumps it, in this tab and the other open tabs
- the server answers private, max-age=60, must-revalidate, so a stale copy
lives for a minute at most and then costs one 304
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
