When OIDC_RESOURCE_SERVER_ID is set, prefix resource scopes with the
identifier when forwarding to the IdP (e.g., calendar.read becomes
https://example.com/calendar.read). Required for IdPs like AWS Cognito
that mandate {resource_server_id}/{scope} format for custom scopes.
OIDC standard scopes (openid, profile, email) are forwarded as-is.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>