Autosave and Post Locking Update 2/2

A quick update on status!

Earlier this week, the initial run at the Heartbeat API went in. @azaozz is continuing to work on it, and flesh out the API further ( #23216 ).

Tonight, the initial post lock view for the post listing was committed [23355] along with a temporary icon:
new_lock

I took a look over an older version of the NYT plugin kindly contributed on #18515.
For discussion, I’m including a few examples of the UI/UX from the workflow included in it below.
We don’t necessarily think everything here is a good idea for core (for instance, the “get me out” buttons wouldn’t be necessary), and will likely go a different route for UI, but hoping to get a bit of discussion going regarding the UI/UX flow for the project.

Lock table:
nyt_lock

Lock table user mouseover:
nyt_lock_notice

Popup for lock within Post Editor:
nyt_lock_popup