I would guess that in these cases you would just not allow users to self-delete their accounts? But for most users and providers of Chatto I think automatic right-to-deletion compliance sounds nice :)
Different users (operators of Chatto servers) will have different requirements for this, so it's pretty much "configurable" in the sense that eg. a business that's hosting a Chatto server for their employees can disable shredding account deletion and just deactivate accounts instead, leaving their data intact.
I wouldn't know. With the post mentioning teams and slack I just got the feeling it was on the cards, so I thought it was worth posting that in case it hadn't occurred to them.
What does implementing soft-delete have to do with data storage though? If you just set up an S3-compatible backend like the docs offer you then have data persistence out of the box, no?