New actions to cancel menu & accept-and-hold

Hello o/

When using the vi mode, when the completion menu is open, there is no way to cancel/hide the menu while staying in insert mode (pressing escape will hide the menu but also go to normal mode which I ~never want).
👉 I'd like to have a MenuCancel action to cancel the menu without changing the current mode.

Related to that, if I type echo f in a directory with files foobar & foobaz, the input will be changed to foo (the longest common text of the completion candidates), then when pressing escape to try to cancel the menu, the original input is not restored (I am left with echo foo instead of echo f.
I don't know if this should be filed as a bug report, but MenuCancel should restore the original input 🙏

Another menu action I'd I'm found of in zsh is the ability to accept current completion but keep the exact same completion menu open (and moving the selected completion to the next).
👉 I'd like to have MenuAcceptAndHold to accept current selection, append a space + what was used for previous completion and continue showing the completion menu.
Selecting the next entry could be moved avoided if we can execute multiple actions in a keybinding 🤔
(note: related to #624 asking for something like a MenuAccept action)

References

Zsh Line Editor (ZLE) has bindable actions do that:

• send-break to cancel current editor function (e.g. the completion menu)
• accept-and-hold to accept current selection but keep completion menu open

Start with the vi-mode completion menu and the existing action and keybinding entry points. Define how MenuCancel restores the original input without changing mode, and how MenuAcceptAndHold accepts the current selection while keeping the menu open; verify both behaviors against the examples in the issue and the related #624 request.