Closes#116.
Deletes config/models.yaml, internal/config/models.go (LoadModels, ModelFor),
its test, the ModelsFile field on Config, and SUPERVISOR_MODELS_FILE from
.env.example. Option A from the issue.
Merge-gate evidence: negative claim independently re-established (no Go, shell,
Dockerfile, k8s, CI or infra-repo caller); task check exit 0 across both
modules; CI run 7374 green on the PR head.
Co-authored-by: Mathias <mthbqv@gmail.com>