refactor(core,quey): batch flush pending and useState based useAtom

[dai-shi]

While working on #687, I thought there should be an easier impl with useState.
This seems to be working. A few tests have to be tweaked.
Still, it reads a mutable store in render. 🤔

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[dai-shi]

Okay, I don't think this is worth it. We would still need to migrate to uSES eventually.
I will file a smaller PR to just fix some issues found in this PR.