Ship our own Element Call fork build instead of the stock embedded package
(webpack copy repointed to ../element-call/dist, with npm-package fallback), and
rework the in-call room layout to match the Blap design:
- Chat stays in the main pane with the call as a compact right-hand column;
when someone shares a screen the call takes prominence in the main pane and
chat moves to the side column (never hidden). Driven by a same-origin
screenshare signal from the EC fork.
- Camera-off: pass the `blapVideoMuted` flag to EC and drop the old (unreliable)
widget-action mute code.
- Room list already lists in-call members under voice channels; add an
"IN THE CALL" header to the call column.
- Hide redundant RTC call-notification ("Video call") pings from the timeline.
- Room header: remove the now-redundant chat, threads and member-facepile
buttons; keep info working over the call (call stays mounted).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>