I had the following thought for lists you create yourself:
* Create list items with item-uri = list rkey + item did
Then the membership test reduces to a check if the item exists.
But that does not work for lists created through other means.
the official app just queries every list membership you've ever made and then finds ones relevent for a given list/person. I think just a new endpoint is needed
Yes. I am doing the same now. Would be good if there would a new endpoint to check list membership.
The backend must already have it. I tried to add the same DID twice. The second request succeeds, but the DID is only once on the list.