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.application/Roles/RoleService.cs

@@ -0,0 +1,118 @@
+using AutoMapper;
+using Mws.Application.Common;
+using Mws.Application.Permissions;
+using Mws.Domain.Roles;
+
+namespace Mws.Application.Roles;
+
+public class RoleService(IUnitOfWork uow, IMapper mapper) : IRoleService
+{
+    public async Task<List<RoleDto>> GetRolesAsync(CancellationToken ct = default)
+    {
+        var roles = await uow.Roles.GetAllWithPermissionsAsync(ct);
+        return mapper.Map<List<RoleDto>>(roles);
+    }
+
+    public async Task<RoleDto> GetRoleAsync(Guid id, CancellationToken ct = default)
+    {
+        var role = await uow.Roles.GetByIdWithPermissionsAsync(id, ct)
+            ?? throw new NotFoundException("Role not found");
+        return mapper.Map<RoleDto>(role);
+    }
+
+    public async Task<RoleDto> CreateRoleAsync(SaveRoleRequest request, CancellationToken ct = default)
+    {
+        var name = request.Name.Trim();
+        if (string.IsNullOrWhiteSpace(name))
+        {
+            throw new BadRequestException("Role name is required");
+        }
+
+        if (await uow.Roles.ExistsByNameAsync(name, null, ct))
+        {
+            throw new BadRequestException("Role name already exists");
+        }
+
+        var now = DateTime.UtcNow;
+        var role = new Role
+        {
+            Id = Guid.NewGuid(),
+            Name = name,
+            IsSystem = false,
+            CreatedAt = now,
+            UpdatedAt = now,
+            Permissions = BuildPermissions(request.Permissions),
+        };
+
+        uow.Roles.Add(role);
+        await uow.SaveChangesAsync(ct);
+        return mapper.Map<RoleDto>(role);
+    }
+
+    public async Task<RoleDto> UpdateRoleAsync(Guid id, SaveRoleRequest request, CancellationToken ct = default)
+    {
+        var role = await uow.Roles.GetByIdWithPermissionsAsync(id, ct)
+            ?? throw new NotFoundException("Role not found");
+
+        var name = request.Name.Trim();
+        if (string.IsNullOrWhiteSpace(name))
+        {
+            throw new BadRequestException("Role name is required");
+        }
+
+        if (await uow.Roles.ExistsByNameAsync(name, id, ct))
+        {
+            throw new BadRequestException("Role name already exists");
+        }
+
+        role.Name = name;
+        role.UpdatedAt = DateTime.UtcNow;
+
+        uow.Roles.RemovePermissions(role.Permissions.ToList());
+        role.Permissions = BuildPermissions(request.Permissions);
+        foreach (var p in role.Permissions)
+        {
+            p.RoleId = role.Id;
+        }
+
+        await uow.SaveChangesAsync(ct);
+        return mapper.Map<RoleDto>(role);
+    }
+
+    public async Task DeleteRoleAsync(Guid id, CancellationToken ct = default)
+    {
+        var role = await uow.Roles.GetByIdAsync(id, ct)
+            ?? throw new NotFoundException("Role not found");
+
+        if (role.IsSystem)
+        {
+            throw new BadRequestException("Cannot delete a system role");
+        }
+
+        if (await uow.Users.ExistsByRoleIdAsync(id, ct))
+        {
+            throw new BadRequestException("Cannot delete a role that is assigned to accounts");
+        }
+
+        uow.Roles.Remove(role);
+        await uow.SaveChangesAsync(ct);
+    }
+
+    private static List<RolePermission> BuildPermissions(List<PermissionEntryDto> entries)
+    {
+        var byScreen = entries.Where(e => ScreenCatalog.Keys.Contains(e.Screen)).ToDictionary(e => e.Screen);
+
+        return ScreenCatalog.Keys.Select(key =>
+        {
+            byScreen.TryGetValue(key, out var entry);
+            return new RolePermission
+            {
+                Screen = key,
+                CanView = entry?.CanView ?? false,
+                CanCreate = entry?.CanCreate ?? false,
+                CanEdit = entry?.CanEdit ?? false,
+                CanDelete = entry?.CanDelete ?? false,
+            };
+        }).ToList();
+    }
+}