RT state managment and rectangle support

dotnet/AipsCore/Application/Models/Whiteboard/Query/GetWhiteboardInfoRT/GetWhiteboardInfoRTQuery.cs

@@ -0,0 +1,5 @@
+using AipsCore.Application.Abstract.Query;
+
+namespace AipsCore.Application.Models.Whiteboard.Query.GetWhiteboardInfoRT;
+
+public record GetWhiteboardInfoRTQuery(Guid WhiteboardId) : IQuery<Infrastructure.Persistence.Whiteboard.Whiteboard>;

dotnet/AipsCore/Application/Models/Whiteboard/Query/GetWhiteboardInfoRT/GetWhiteboardInfoRTQueryHandler.cs

@@ -0,0 +1,40 @@
+using AipsCore.Application.Abstract.Query;
+using AipsCore.Domain.Common.Validation;
+using AipsCore.Domain.Models.Whiteboard.Validation;
+using AipsCore.Domain.Models.Whiteboard.ValueObjects;
+using AipsCore.Infrastructure.Persistence.Db;
+using Microsoft.EntityFrameworkCore;
+
+namespace AipsCore.Application.Models.Whiteboard.Query.GetWhiteboardInfoRT;
+
+public class GetWhiteboardInfoRTQueryHandler
+    : IQueryHandler<GetWhiteboardInfoRTQuery, Infrastructure.Persistence.Whiteboard.Whiteboard>
+{
+    private readonly AipsDbContext _context;
+
+    public GetWhiteboardInfoRTQueryHandler(AipsDbContext context)
+    {
+        _context = context;
+    }
+    
+    public async Task<Infrastructure.Persistence.Whiteboard.Whiteboard> Handle(GetWhiteboardInfoRTQuery query, CancellationToken cancellationToken = default)
+    {
+        var whiteboard = await GetQuery(query.WhiteboardId).FirstOrDefaultAsync(cancellationToken);
+
+        if (whiteboard is null)
+        {
+            throw new ValidationException(WhiteboardErrors.NotFound(new WhiteboardId(query.WhiteboardId.ToString())));
+        }
+        
+        return whiteboard;
+    }
+    
+    private IQueryable<Infrastructure.Persistence.Whiteboard.Whiteboard> GetQuery(Guid whiteboardId)
+    {
+        return _context.Whiteboards
+            .Where(w => w.Id == whiteboardId)
+            .Include(w => w.Memberships)
+            .Include(w => w.Owner)
+            .Include(w => w.Shapes);
+    }
+}