[store-zustand] race conditions with states

[Ainias]

If you send multiple updates from different content scripts simultaniously, only the last one will be saved.
In my example I have a record inside the store. My state is

{
characters: Record<string, string[]>
} 

And I open multiple iFrames, each one collecting data for a single character.
Often times the data is collected at the same time, so two or more content scripts are sending the full state to the backend-script. But they do not have the state (character infos) from the other iFrames and therefore only the last state is saved correctly.

Maybe a state-update method (like shallow-merge/deep-merge) could be added to the initPegasusZustandStoreBackend-State. And deleting of states must be set to null or undefined directly?