Behavior: Triggers generation of system-level statistics. When forceReload is true, statistics are regenerated even if they already exist for the current period.

Authorization: Requires an authenticated user via the class-level [Authorize] attribute. Additionally, the user must be an admin (checked via IsAdminUser).

Side Effects: Generates and persists system statistics records. When forceReload is true, existing statistics may be overwritten.

Error Scenarios: Returns 400 if the user is not an admin or the statistics generation fails. Throws a VibrantException if the user lacks admin permissions.