I want question the import references.
From the comment in
a short reference provided by the client to group multiple files in the same import
Currently it is implemented as a simple ISO DateTime string. User can add
?import=2022-11-16T17%3A45%3A29.784Z query parameter to see the status of uploaded songs. I doubt that anyone remembers the reference of any import and if they even do, it's not a pleasant solution in my opinion.
I think we may just group uploads not by import reference but by simply library id. The logic would be simpler, database footprint smaller, and it would be also backwards compatible as we already have the library id assigned to every upload. We could then split all uploads into 4 tabs:
uploading tab would be handled only by client and the entries here are just files that are being uploaded
processing tab would show all uploads that are being processed
errored tab would show a paginated table with errored uploads
imported tab would show a paginated table with all uploads that have been successfully uploaded