Failing tests for #181, against a
stand-in Ente server with real encryption: the client leaves out a row it
cannot decrypt or parse and reports it, and quak backup stores every other
file, records each such file in failures.json, names each such album, exits
1 while any remain, and drops each once it decrypts or is deleted.
Model: opus-5-5
Adds collectionsSince/filesSince taking a starting cursor, returning the resumable max-updationTime cursor and a separate list of tombstoned ids; filesSince throws instead of looping when the server reports hasMore without advancing (closes#7). listCollections/listFiles stay as thin, unaffected wrappers.
Model: opus-4-8