List guardrail validators and actions

Returns the static catalog of guardrail validator types and enforcement actions.

Use validators[].id as type and actions[].id as on_fail when building entries in PUT /applications/{applicationId}/guardrails. Each catalog validator includes an input / output flag indicating where it may be used.

For content-safety, validators[].config.categories lists the available safety categories (id, name, description). When configuring an application via PUT, set config.categories to an array of selected category id strings (for example ["violent-crimes", "hate"]). At least one category is required.

For pii, validators[].config.entities lists the available PII entity types (id, name, description, group). When configuring via PUT, set config.entities to an array of selected entity id strings (for example ["EMAIL_ADDRESS", "PHONE_NUMBER"]). At least one entity is required.