Shares a job's attachment gallery via email, SMS, or link. For EMAIL, to/subject/body are required. For SMS, phone_numbers/body are required (requires the Zuper Connect system-notification policy). via: LINK is accepted but, for this job-scoped path, does not actually generate a shareable link (that behavior exists only on the generic folder-share variant of this same handler) — effectively a no-op for LINK on this endpoint.