Revision for task [[ https://linear.app/comm/issue/ENG-1430/compute-messagestorethreads-based-on-messages-in-sqlite | ENG-1430 ]].
We do want to stop persisting messageIDs since they can be deterministically generated based on SQLite output (and we already do it in code).
Transformation is needed to provide ability to omit deeply nested fields, also, outbound function (second argument) assigns an empty array to `messageIDs` before re-hydration because we always expect this field to be defined.