Implement cloud sync

[Garciat]

Goals

• Maintain decoupling between the core data model & flow and the cloud sync stack.
  • For example, it is possible to implement everything with Firebase because it is reactive and offline-capable. That means business logic and UI components could directly use Firebase object streams.
  • But I don't want the app to be tied to Firebase in a way that restricts or complicates moving to a different provider.
  • Also, not every user wants cloud sync. By default, the app should only sync to local storage.
• Model all entities (presets, history records, config?) uniformly.
  • Currently, presets are stored in LocalStorage and history records in IndexedDB. So we have essentially two different storage layers. It would be good to have just one.

Ideas

• Implement a meta-hook that wraps IDB and provides:
  • Input:
    • A concrete subtype of IDB's DBSchema
  • StoreProvider
    • A context provider that wraps the app and enables the actual hooks.
  • useStoreQuery
    • Returns a reactive query (TODO: read react-query)
  • useStoreRecord
    • Returns a reactive record by key
  • useStoreDelete
    • Returns a delete function for records by key
  • useStoreUpdate
    • Returns an update function for records by key
  • useStoreEvents
    • Returns a sort of stream of store change events. Used by sync providers.