The supervisor polls /internal/engine-state (not /admin/api/status) to
populate each engine's loaded_models in the registry, which the front then
aggregates for the models page. That endpoint only read .models, so a
whisper-server running on a secondary engine still showed as not loaded.
Fold each running server (id + `audio:` alias) into its loaded_models.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>