Reconcile history task items in queue store

[christian-byrne]

Before:

After:

Assumption is made that history items don't change in backend in a way that's meaningful to frontend.

As discussed in:

• Queue panel becomes less responsive over time #241

[huchenlei]

@christian-byrne
Please take a look at #393. The queueIndex is strictly auto incrementing, so I think tracking the last seen queueIndex is sufficient for determine whether the item is new in the history queue.

[christian-byrne]

@christian-byrne Please take a look at #393. The queueIndex is strictly auto incrementing, so I think tracking the last seen queueIndex is sufficient for determine whether the item is new in the history queue.

Very nice, that makes it a lot smoother