- Add CreatedAt timestamp to CreateGroupBead() in beads_group.go - Add CreatedAt timestamp to CreateChannelBead() in beads_channel.go - Check channel status before sending in router.go sendToChannel() - Reject sends to closed channels with appropriate error message Closes: gt-yibjdm, gt-bv2f97 Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>