feat: add support for macOS modifier keys

[TomasWeisss]

Summary

Changed the modifier key handling for text navigation, deleting, and history to work on MacOS.

Why

MacOS uses Option for skipping/deleting by words, and Command for undo/redo. The current setup didn't account for this, so the navigation didn't work on MacOS.

Validation

• Automated: Tests modified to use MacOS modifier keys when on MacOS, all pass.
• Manual: Verified to work on MacOS.
• Screenshot/video (if UI changed): N/A

Notes

• Breaking changes: N/A
• Docs updated: N/A

[srothgan]

@TomasWeisss Thanks for the PR. This looks like a useful improvement. Since I am working on Windows, I didnt catch that.

I would just ask for two focused changes tied to the Command-key behavior added here:

1. Can you also support standard macOS redo as Shift + Command + Z (KeyModifiers::SUPER | KeyModifiers::SHIFT with KeyCode::Char('z')). Keeping Command + Y as an extra alias is fine. This from documentation looks like the standard combination for macOs but I could be wrong.

2. If we rely on KeyModifiers::SUPER, we should enable crossterm keyboard enhancement mode on startup and restore it on shutdown. The centralized place for that is src/app/terminal_runtime/modes.rs, where CHAT_STARTUP_ACTIONS and SHUTDOWN_RESTORE_ACTIONS are applied. The implementation would be roughly:

use crossterm::event::{KeyboardEnhancementFlags, PopKeyboardEnhancementFlags, PushKeyboardEnhancementFlags};

execute!(
    stdout,
    PushKeyboardEnhancementFlags(KeyboardEnhancementFlags::DISAMBIGUATE_ESCAPE_CODES)
)?;

// during terminal restore/shutdown
execute!(stdout, PopKeyboardEnhancementFlags)?;

crossterm documents that SUPER, HYPER, and META require KeyboardEnhancementFlags::DISAMBIGUATE_ESCAPE_CODES, so I think we should enable that mode here if this PR depends on Command-key shortcuts.

[TomasWeisss]

That's a good recommendation, definitely should follow system shortcuts. I've run into some issues however.

The updated shortcuts did not work without the keyboard enhancement as you predicted. However, the location you mention (rc/app/terminal_runtime/modes.rs) only exists in your refactor branch. So I explored if I could rebase the feature on it, but I found the branch is not very stable yet. I wasn't able to run it out of the box (failed to construct ratatui inline chat terminal: The cursor position could not be read within a normal duration). After adding a default cursor position fallback, it did run, but didn't position and/or overdraw the existing terminal contents correctly.

What would you advise- I finish this feature on main and you or I have to possibly re-integrate in the refactor, or wait until after the refactor?

[srothgan]

Sorry for that. I was fully focused on the refactor and pointed you at a file from my refactor branch.

On main branch, the keyboard enhancement setup already lives in src/app/mod.rs via resume_terminal() / suspend_terminal(), so please do not rebase this onto the refactor branch and do not spend time moving terminal setup around.

For this PR, I think the only change I would still ask for is the macOS redo shortcut: please support Shift + Command + Z (KeyModifiers::SUPER | KeyModifiers::SHIFT with KeyCode::Char('z')). Keeping Command + Y as an extra alias is fine.

After that, we can merge the PR. I will handle any refactor-branch integration later. Thank you for your help

[TomasWeisss]

Modified to use the standard Command + Shift + Z for redo. I also modified the history method to always return true if the shortcut was recognized, even if it didn't perform an action, as pressing Redo and having it suddenly start typing capital Z was very strange and not standard behavior.

[srothgan]

Looks good, but we need to handle macOS, Windows and Linux so we can not just replace CTRL with the macOS native command. We need to make the command key OS-aware. Here is my idea for that:

#[cfg(target_os = "macos")]
const CMD_MOD: KeyModifiers = KeyModifiers::SUPER;

#[cfg(not(target_os = "macos"))]
const CMD_MOD: KeyModifiers = KeyModifiers::CONTROL;

[TomasWeisss]

My apologies, I accidentally changed the key for the Windows branch. I used the opportunity to centralize the handling into a few constants at the top of keys.rs, which are exported as to be available in tests as well.

[srothgan]

Thank you, looks good 👍

[TomasWeisss]

Great! Is there anything more I need to do or will you merge it?