system/public/menuband: privacy lists update-check + manual crash-upload endpoints
The "nothing leaves your Mac" tagline was no longer accurate now that
the popover does an hourly latest.json check and exposes a manual Send
button for any captured crash report. Both endpoints are now described
in full (URL, trigger, what's sent), and the third-parties section
names the CDN/VPS path. Also adds a dark-mode block matching the
rest of the menuband site.