This MR addresses #4404 following the approach suggested
[here](https://github.com/ghostty-org/ghostty/issues/4404#issuecomment-2708410143).
Implementing the behavior known e.g. from Putty or Windows Terminal.
The following configuration values for `right-click-action` are
provided:
* `context-menu` - Show the context menu.
* `paste` - Paste the contents of the clipboard.
* `copy` - Copy the selected text to the clipboard.
* `copy-and-paste` - Copy the selected text to the clipboard, paste if
nothing is selected.
* `ignore` - Do nothing, ignore the right-click.
I followed #5935 for getting an idea on where to start. I hope this to
be a temporary solution until "bindable mouse bindings" are introduced.
This is my first time writing Zig code, so I am happy to incorporate any
feedback.
Thank you all very much for your work!
5745f5048c