feat: add queries for group

Application/Cqrs/Group/Queries/GetGroupDetails/GetGroupInfoQueryHandler.cs

@@ -0,0 +1,28 @@
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+using Mirea.Api.DataAccess.Application.Common.Exceptions;
+using Mirea.Api.DataAccess.Application.Interfaces.DbContexts.Schedule;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Mirea.Api.DataAccess.Application.Cqrs.Group
+    .Queries.GetGroupDetails;
+
+public class GetGroupInfoQueryHandler(IGroupDbContext dbContext) : IRequestHandler<GetGroupInfoQuery, GroupInfoVm>
+{
+    public async Task<GroupInfoVm> Handle(GetGroupInfoQuery request, CancellationToken cancellationToken)
+    {
+        var discipline = await dbContext.Groups
+            .Include(g => g.Faculty)
+            .FirstOrDefaultAsync(g => g.Id == request.Id, cancellationToken)
+                         ?? throw new NotFoundException(typeof(Domain.Schedule.Group), request.Id);
+
+        return new GroupInfoVm()
+        {
+            Id = discipline.Id,
+            Name = discipline.Name,
+            Faculty = discipline.Faculty?.Name,
+            FacultyId = discipline.FacultyId
+        };
+    }
+}