List all scope groups via JWT Bearer Token authentication (External API).

This endpoint provides the same functionality as GET /api/internal/list-groups but uses modern JWT Bearer token authentication.

Authentication: JWT Bearer token (via nginx X-User header) Authorization: Requires valid JWT token from auth system

Response: Returns a list of all groups and their synchronization status.

Example:

curl -X GET https://registry.example.com/api/servers/groups \
  -H "Authorization: Bearer $JWT_TOKEN"