The schedule modal took only a plain body and rebuilt {body, msgtype},
dropping formatted_body, m.mentions and m.relates_to. It now receives
the full IContent; an unedited body is sent verbatim, an edited body
drops the now-stale formatted_body but keeps mentions and the reply/
thread relation. Reschedule from the tray preserves them too.
Unit-tested (mergeScheduledBody).
Fixes#36
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA
