Refactor the invitation acceptance flow to use a landing page pattern:
- GET shows invitation details (team name, role, confirmation button)
- POST processes the acceptance with proper form submission
- Remove unused revoke GET route (handled by Livewire component)
- Add Blade view for the invitation landing page
- Add feature tests for the new invitation flow
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
