A [LOC] DM to a room server is delivered as a plain DM, not reposted to the
room's members, so a room server can't act as a live-share broadcast target.
The main contact picker already lists CHAT contacts only, but a favourited
room server still showed up in the LEFT/RIGHT quick-cycle — skip it there,
and reject a room in commitPickTargetDM as a backstop if the room-mode list
is ever reachable during target pick.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>