Returns the project's current live state (theme settings, pages with their items, and page assignments) as the versioned import/export JSON. This is the same file the dashboard Export button downloads and POST /projects/{projectId}/import accepts.

• Built from the live rows at request time; page and item ids are regenerated.
• Not a backup: backups are point-in-time archives under /projects/{projectId}/backups.
• Sent with content-disposition: attachment and cache-control: private, no-store.
• Read-only.

Required scope: project:manage