Queue management for running cells.

### Problem

There is a current limitation in Ipykernel where it is not possible to modify the order or cancel operations of queued cells once they have been set. This limitation can disrupt a smooth workflow and may result in the loss of variables, a dead kernel, or other issues if not managed carefully.

### Proposed Solution

To address this issue, I suggest implementing a feature that allows dynamic modification of queued cells while a cell is running or a queue is active. This can be achieved through two possible approaches:

1. Introduce a separate section where the queue is displayed, providing options to move or delete items from the queue.

2. Display the queued items along with their order within the cell body itself, allowing users to edit the order directly.

### Additional context

Implementing such a feature would greatly benefit users, preventing the loss of valuable time caused by inadvertently queuing the wrong cell. And I can take up the responsibility to ship out this feature once approved. Thanks!

Start by tracing how queued cells are represented and controlled between Jupyter Notebook and ipykernel. Compare the two proposed queue interfaces and determine how reordering and cancellation should work while a cell is running. Done means users can safely inspect, reorder, and cancel queued cells without disrupting the kernel.

Written by the indexing model from the issue text.