Data protection, @dce@hashnix.club! :-D

This revealed another bug in my client that I still need to fix at some point. Inserting an empty set of messages failed with an SQL logic error. Whoops. I didn’t think about that corner case.

Finally, I added some tests and fixed this. After updating the feed metadata, I now just return early and do not attempt to build an SQL multi-value INSERT statement. Easy-peasy.