- CommunicationHub.tsx: main layout shell with sidebar + message area
- ChannelSidebar.tsx: channel list with unread badges and filter bar
- MessageList.tsx: message display with threading and empty states
- MessageItem.tsx: message bubble, task comment bubble, agent avatar
- MessageComposer.tsx: message input, task discussion composer, compose modal
- ChannelHeader.tsx: channel info bar with stats
- channel-utils.ts: shared channel derivation and message filtering logic
- Original communication.tsx replaced with backward-compatible re-exports
- All sub-components under 300 lines, TypeScript compilation passes
ZacharyZhang-NY