Replace the home page with a portal selector showing three access paths:
- Organisation Portal → /org/login
- Chapter Portal → /login
- Member Portal → /member-login
Remove /signup and its BFF route — tenants are now only created by org
owners through the org portal or assigned by super admins. Self-serve
community creation is no longer supported.
Update sidebar to bypass auth guard for / (exact match) without
accidentally matching all paths via startsWith.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
maaz519