This commit adds the thread index and individual thread
in the index list unread indicators, and wires up the message
bus events to mark the threads as read/unread when:
1. People send a new message in the thread
2. The user marks a thread as read
There are several hacky parts and TODOs to cover before
this is more functional:
1. We need to flesh out the thread scrolling and message
visibility behaviour. Currently if you scroll to the end
of the thread it will just mark the whole thread read
unconditionally.
2. We need to send down the thread current user membership
along with the last read message ID to the client and
update that with read state.
3. We need to handle the sidebar unread dot for when threads
are unread in the channel and clear it based on when the
channel was last viewed.
4. We need to show some indicator of thread unreads on the
thread indicators on original messages.
5. UI improvements to make the experience nicer and more
like the actual design rather than just placeholders.
But, the basic premise around incrementing/decrementing the
thread overview count and showing which thread is unread
in the list is working as intended.
This commit adds an initial thread list UI. There are several limitations
with this that will be addressed in future PRs:
* There is no MessageBus reactivity, so e.g. if someone edits the original
message of the thread it will not be reflected in the list. However if
the thread title is updated the original message indicator will be updated.
* There is no unread functionality for threads in the list, if new messages
come into the thread there is no indicator in the UI.
* There is no unread indicator on the actual button to open the thread list.
* No pagination.
In saying that, this is the functionality so far:
* We show a list of the 50 threads that the user has most recently participated
in (i.e. sent a message) for the channel in descending order.
* Each thread we show a rich excerpt, the title, and the user who is the OM creator.
* The title is editable by staff and by the OM creator.
* Thread indicators show a title. We also replace emojis in the titles.
* Thread list works in the drawer/mobile.