Commit MWS backend source tree

The ASP.NET Core solution (mws.api/mws.application/mws.domain/
mws.infrastructure) existed only as untracked working files. Adding
it to version control, plus a .gitignore for build output and local
tooling directories, so the CQRS/mediator refactor plan has a real
git history to branch and diff against.

mws.domain/Roles/Role.cs

@@ -0,0 +1,12 @@
+namespace Mws.Domain.Roles;
+
+public class Role
+{
+    public Guid Id { get; set; }
+    public string Name { get; set; } = string.Empty;
+    public bool IsSystem { get; set; }
+    public DateTime CreatedAt { get; set; }
+    public DateTime UpdatedAt { get; set; }
+
+    public List<RolePermission> Permissions { get; set; } = [];
+}