A draft is keyed by slot id, and a slot keeps its id when it is pointed at a
different node. An unsaved steps stayed attached across a swap -- and since
most samplers declare steps, and the server only refuses an input the new node
does NOT declare, it was written on the next Save with nothing saying it had
never been chosen for that node.
The fake server in the tests did not implement replace, which is why no test
could see it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
