Operations keep their upstream tags as the second grouping level, and
each service becomes an x-tagGroups entry (first level). Tag names
shared by several services are disambiguated with the service name.
The intro renders one section per service with the upstream spec's
title and info.description (the admin-entered description overrides).
The /docs renderer switches from Swagger UI to Scalar, which renders
x-tagGroups as a nested sidebar, keeps try-it-out, and gets the API
key pre-filled into its authentication panel.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
