The registry entry is cleared by submitCurrent() (and again by
showDialog()) BEFORE applyCltDialog() runs the getNext*() reads, so
getValueOrDefault() - which looked the session up via the registry -
always saw null and fell back to every field's default: any value set
via POST /mcp/dialog/values was silently lost and OK re-applied the
loaded config. The dialog now keeps its OWN session reference for the
reads and the await; the registry cleanup clears only its own session
(covers the timeout path without clobbering a newer dialog).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>