Adds an ephemeral chat inside meetings (relayed over the meeting signaling socket,
not persisted). A chat button in the meeting bar (with an unread badge) opens a
brand-styled panel: pick "Everyone" or a specific participant (private), send with
Enter/Send. Direct messages are marked private on both sides. Works for guests too.
Chat state resets when you leave the call.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>