Update to dotnet 9.0, add user roles, MatchStats and OpenApi/Scalar in dev

LaDOSE.Src/LaDOSE.Entity/ApplicationRole.cs

@@ -0,0 +1,17 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace LaDOSE.Entity
+{
+    /// <summary>
+    /// A role a user can hold, stored in the pre-existing <c>applicationrole</c> table.
+    /// Rows are reference data seeded by Sql/2026-08-05_roles.sql, not created at runtime.
+    /// </summary>
+    public class ApplicationRole
+    {
+        public int Id { get; set; }
+
+        [Required]
+        [MaxLength(50)]
+        public string Name { get; set; }
+    }
+}