`limactl shell`: show the sync dialog (Yes/No/View the changed contents) when a specific key is pressed

Currently, `limactl shell` shows the sync dialog (Yes/No/View the changed contents) only on leaving from the shell:
```console
$ limactl shell --sync . default touch new_file
INFO[0000] Syncing host current directory(/Users/suda/test) to guest instance...
INFO[0000] Successfully synced host current directory to guest(/home/suda.guest/Users/suda/test) instance.
? ⚠️ Accept the changes? (added: 1, deleted: 0, modified: 0) [Use arrows to move, type to filter]
Yes
No
> View the changed contents
```

It should be possible to sync back files without leaving from the shell.
When a specific key (e.g., F1) is pressed, limactl should hook the keyboard input and show the sync dialog.