Second template axis (org identity: letterhead, footer, signature,
margins) server-side: OrgTemplateStore with JSON version history,
publish/rollback, sent-brief version pinning, admin role + capability,
5 admin endpoints, org-logo upload category. FE seam widened only
(Role/Capability unions, interceptor); WP-24/26 consume it.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
