Messaging · Channels: the chat list, its rows, a channel's head and its pins

ChannelList sets chats down in sections, each a list: a press, an arrow
or Enter opens one, and the open chat is lit. A title names one section,
and a section holds a chat. ChannelItem shows a hash or a lock, its
unread count, a pin when pinned, and goes quiet when muted.
DirectMessageItem shows a person's initials with their presence. Unread
names stand out through ListItem's new strong; muted channels and
offline people go quiet through its quiet. ChannelHeader holds the name
and topic beside members, pins and a call, wrapping by the header rule.
PinnedMessages lists pins newest first; a press, an arrow or Enter opens
one, and Unpin lets one go. With none it shows a line and takes no Tab
stop.

tasks/ch21-30.md

@@ -320,33 +320,45 @@
 - [x] DownloadManager
 - [x] StorageUsage → `data_display::UsageBar`
 
-## T28 Messaging — `src/messaging`
+## T28a Messaging · Channels — `src/messaging`
 
-- [ ] ChannelList / ChatList
-- [ ] ChannelItem
-- [ ] DirectMessageItem
+- [x] ChannelList / ChatList
+- [x] ChannelItem
+- [x] DirectMessageItem
+- [x] ChannelHeader
+- [x] PinnedMessages
+
+## T28b Messaging · Messages
+
+- [ ] ChatMessage
 - [ ] MessageThread
 - [ ] ThreadPanel
-- [ ] ChatMessage
 - [ ] UnreadDivider
 - [ ] MessageReactions → `collab::Reactions`
 - [ ] ReadReceipt
 - [ ] TypingIndicator → `motion::TypingIndicator`
+
+## T28c Messaging · People
+
 - [ ] MemberList
 - [ ] UserProfileCard
 - [ ] OnlineStatus
 - [ ] StatusSetter
-- [ ] VoiceCallBar
-- [ ] VideoCallGrid — host frames
-- [ ] ScreenShareView — host frames
+
+## T28d Messaging · Calls
+
 - [ ] CallControls
 - [ ] ParticipantTile
+- [ ] VideoCallGrid — host frames
+- [ ] ScreenShareView — host frames
+- [ ] VoiceCallBar
 - [ ] IncomingCallDialog
+- [ ] HuddleIndicator
+
+## T28e Messaging · Stickers and GIFs
+
 - [ ] StickerPicker
 - [ ] GifPicker — host images
-- [ ] PinnedMessages
-- [ ] ChannelHeader
-- [ ] HuddleIndicator
 
 ## T29 Mail — `src/mail`