Allow LeftAlt and RightAlt mapping on MacOS

Hi!

I'm attaching two patches to disambiguate between Left Option and Right Option on MacOS.

Sometimes one wants to just bind one side and let the other pass through to the OS (in my case to support writing special characters).

I'm not a Rust-programmer and have no real clue how to properly support this (but I want to apply a patch to use GlideWM, so I with assistance of AI created two patches). Perhaps this can be upstreamed, but I don't want to flood your pull requests with bad code so I attach the patches here as a feature request.

They apply cleanly to d641140

Best,
Isak

[0001-hotkey-add-ALT_LEFT-and-ALT_RIGHT-side-specific-modi.patch](https://github.com/user-attachments/files/25681955/0001-hotkey-add-ALT_LEFT-and-ALT_RIGHT-side-specific-modi.patch)

[0002-hotkey-macos-match-side-specific-Alt-hotkeys-using-d.patch](https://github.com/user-attachments/files/25681956/0002-hotkey-macos-match-side-specific-Alt-hotkeys-using-d.patch)

Review the two attached patches against commit d641140 and trace the existing hotkey mapping and macOS matching paths. Confirm that LeftAlt and RightAlt can be bound independently while the unbound side passes through to macOS; completion should preserve existing hotkey behavior and apply the requested side-specific mappings.

Written by the indexing model from the issue text.