A clear Home page for guests

Guests now start with a simple guide and cards for the projects and work shared with them.

Guest users now open Home after they sign in. The page explains why they are in Leadtime and lists the projects shared with their organization.

Each project card shows guest-visible open tasks, tasks assigned to the guest, forms to complete, and documentation pages. A clear empty state appears when no project is shared. Configurable dashboards remain available to workspace users only.