Issue #2246 — live meeting row
A sidebar row has one line (avatar, name, time) and never shows a message preview, so "no preview line" versus "normal preview line" shows up as the time label. Two options for the empty row: 1a shows the meeting's start time, 1b shows no time.
1a. Live, empty — start time
1b. Live, empty — no time
2. Live, first message
The meeting sits first among recent conversations, by the time it went live. Once a message arrives the row shows that message's time and an unread count; the dot stays on.
3. Ended, still empty — during, then after
Nobody typed, so when the meeting ends the row goes away, exactly as today.
4. Ended, with messages
5. Pinned, live, empty
4: the row stays in its place as an ordinary conversation, no dot. 5: the same rule applies to a pinned meeting chat.