Deleting the only zone in the UI reloaded the entry with no zones, and
min() over an empty set of models raised during setup, so the entry
failed to load. Counts and learning progress now default to 0, and the
status reads "no_zones" until a zone is added again; adding one resumes
normally. HA Core regression test included.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>