perf: adopt optimistic state updates and avoid blocking UI for level operations

[shamilovtim]

in the future we'll want a layer that:

• asynchronously updates level under the hood (but doesn't block render)
• adopts optimistic updates in order to increase the perception of speed in the UI
• reads from a memory based store (like React Query)
• we'll want to finetune when and how react query rehydrates from level
• react query should not block the UI when it rehydrates from level