feat: refactor organisation pages with tabs, members tab, and danger zone

Organizer org page (/organisation):
- Timestamps moved below title as muted caption
- VTabs with Algemeen (details) and Leden (members) tabs
- Members content embedded from separate page with full functionality:
  invite, edit role, change email, remove, pending invitations

Platform org detail (/platform/organisations/[id]):
- Timestamps moved below title alongside slug
- VTabs with Algemeen and Leden tabs
- Danger zone redesigned: type-to-confirm delete dialog, disabled
  Transfer Ownership button with "Nog niet beschikbaar" tooltip

Navigation:
- Removed standalone "Leden" menu item (now a tab on org page)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/app/src/navigation/vertical/index.ts

@@ -17,13 +17,6 @@ export const orgNavItems = [
     to: { name: 'organisation' },
     icon: { icon: 'tabler-building' },
   },
-  {
-    title: 'Leden',
-    to: { name: 'organisation-members' },
-    icon: { icon: 'tabler-users-group' },
-    action: 'read',
-    subject: 'members',
-  },
   {
     title: 'Bedrijven',
     to: { name: 'organisation-companies' },