Method CreateSubtask

backend/Controllers/TasksController.cs:125–145

(int taskId, [FromBody] CreateSubtaskDto dto)

    }

    [HttpPost("{taskId}/subtasks")]
    public async Task<IActionResult> CreateSubtask(int taskId, [FromBody] CreateSubtaskDto dto)
    {
        try
        {
            int userId = GetUserId();
            var subtask = await _taskService.CreateSubtaskAsync(taskId, dto, userId);
            if (subtask == null) return NotFound();

            // Hack: We need the boardId to notify the group. 
            var task = await _taskService.GetTaskByIdAsync(taskId, userId);
            if (task != null)
            {
                await _hubContext.Clients.Group($"board_{task.BoardId}")
                    .SendAsync("TaskUpdated", task);
            }

            return Ok(subtask);
        }
        catch (UnauthorizedAccessException) { return Forbid(); }
    }

    [HttpPut("subtasks/{subtaskId}")]
    public async Task<IActionResult> UpdateSubtask(int subtaskId, [FromBody] UpdateSubtaskDto dto)