feat(spec): book sys_organization.actions.invite_user under the organization feature gate

Claude-Session: https://claude.ai/code/session_01Eey1448sFJ5Z95gbXZh2tG
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

packages/spec/src/kernel/public-auth-features.ts

@@ -121,6 +121,10 @@ export const PUBLIC_AUTH_FEATURES = {
       'sys_team.actions.remove_team',
       'sys_team_member.actions.add_team_member',
       'sys_team_member.actions.remove_team_member',
+      // Fourth mirror of the email-invite entry, at the organization record
+      // page's `record_header` — a `page:header` resolves ids against its own
+      // object's actions only (ruling 6228318638, B′ on #24034).
+      'sys_organization.actions.invite_user',
     ],
     notes: 'Org CAPABILITY gate, not multi-org (cloud ADR-0081 D1).',
   },