Add member management to the platform admin organisation detail page:
- Backend: invite (creates invitation or directly adds existing user),
remove member, update member role endpoints on AdminOrganisationController
- Backend: show endpoint now returns members alongside organisation data
- Frontend: members table with inline role editing, invite dialog,
remove confirmation dialog on /platform/organisations/[id]
- Tests: 7 new tests covering happy paths and edge cases (self-removal,
existing member, non-super_admin denied)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>