Enable/disable or override markup

slug is provider (whole provider) or provider/endpoint (URL-encoded). Personal accounts must send exactly {"enabled": boolean} and receive only endpointSlug plus effective enabled state; markup fields and extra properties are rejected. Enterprise workspaces may update enablement and/or markup. Enablement resolves endpoint override -> provider override -> platform default. Omitting enabled never changes enablement. Sending enabled on a provider slug resets that provider's endpoint-level enablement overrides to inherit while preserving markup overrides.