fix: option as meta when control and command are pressed

[gaelph]

The proposed change is to address issue #1095

It treats the Option key as Meta (or Alt) if either Command, or Control is also pressed. It also treats the Option key as Meta if the other pressed key is a special key (i.e. arrow keys).
In any other scenarios, the Option key behaviour is unchanged.

This allows for users of non-qwerty layouts (such as the azerty layout) to map Control+Alt sequences, while retaining the ability to insert characters that require the use of the option key (including, but not limited to { and [, in the case of the azerty layout).
This replicates the behaviour observed in common terminal emulators such as Kitty, WezTerm and Alacritty.

The "option as alt" settings are still honored and no change of behaviour is to be expected by users of these options.

I am not so happy with the flags.contains("C-") check in KeyUtils.isControlCode(key:, flags:) function, I’d be happy to have suggestions on how to improve that.

[qvacua]

Re. flags.contains("C-"): you could pass modifierFlags to isControlCode() and check contains(.control) since that's what's being checked.