left/right arrow keyboard buffer

### Describe the feature or problem you'd like to solve

When moving the cursor in a prompt or on the `other` part of a multiple choice, the cursor doesn't stop when the finger is raised from the left/right key but the keeps going until the keyboard buffer is completely flushed.

### Proposed solution

stop the editor cursor movement (ignore the rest of the buffer) when the user raises his finger from the key

### Example prompts or workflows

_No response_

### Additional context

_No response_

Start by locating the prompt editor and the multiple-choice “other” input handling, then trace how left/right key events are buffered. Done means cursor movement stops when the key is released and any remaining buffered movement is ignored; verify this in both workflows described.

Written by the indexing model from the issue text.