The decorator was defined inline in console/auth/oauth_device.py. Phase
D will move approve/deny to controllers/openapi/oauth_device/ and the
new SSO branch under the same group needs the same gate. Hoist it to
libs/oauth_bearer.py now so the move stays a pure file rename later.
Behavior unchanged: 503 'bearer_auth_disabled' when ENABLE_OAUTH_BEARER
is off. console/auth/oauth_device.py imports it from libs and drops
the now-unused dify_config / wraps / ServiceUnavailable imports.
Plan: docs/superpowers/plans/2026-04-26-openapi-migration.md (in difyctl repo).