The keeper's hall-announce writes one file on the shared host; the site
serves it at /hall/announcement.json, and the banner shows it with the time
in the reader's own clock, dismissable one notice at a time.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jm2auWk6RP71CjaAb4FMoG