Add the admin + license gate for /api/v2 and ship the first gated
resource, GET /api/v2/admin/projects (AdminProjectList).
The gate reuses the existing v1 middleware functions unchanged —
RequireFeature(license.FeatureAdminPanel) and RequireInstanceAdmin(),
both of which serve 404 on failure. Rather than splitting the single
v2 Huma API into a separate gated sub-group (which would split the
OpenAPI spec and drop admin operations from /api/v2/openapi.json), the
gate is applied as a path-scoped Echo middleware on the shared /api/v2
group, firing only for /api/v2/admin/* and after the token middleware.
This preserves v1's 404-not-403 semantics and keeps admin routes in the
unified v2 spec and Scalar docs.
AdminProjectList lists every project on the instance (archived
included), behind the gate. Adds doc:/readOnly: tags to the shared
Project model so it documents correctly as a v2 schema.
Tests in pkg/webtests/huma_admin_test.go (TestHumaAdminProjects) cover
all three personas: non-admin -> 404, admin without feature -> 404,
admin with feature -> 200 list, plus unauthenticated -> 401.
kolaente