Custom shortcut dialog should capture Cmd/Option/Win chords

[matthewcorven]

The Custom Shortcut dialog currently misses modifier chords on macOS and Windows-key layouts.

Repro:

1. Open the Custom Shortcut dialog.
2. Press Cmd+ or Option+ on macOS, or the Windows key with another key on Windows.
3. Nothing appears in the field; Shift+ does work.

Expected:

• Modifier chords should be captured from key events, not just plain text entry.
• Aliases like cmd/command/meta/win/windows and option/opt should normalize to canonical shortcut storage.
• The UI should display platform-appropriate labels (Cmd/Opt on macOS, Win/Alt on Windows).

This blocks some custom shortcut bindings from being configured on macOS and on keyboards that use the Windows key as the command/meta modifier.

[TomBadash]

Hey @matthewcorven,

When referring to the Cmd/Win key, the standard term is "Super".

That said, you're right, we’ll add aliases for those names to make it more intuitive.

Thanks for the feedback, and I hope you're enjoying Mouser overall!

[matthewcorven]

Thanks @TomBadash. I've reduced the scope of changes on PR 114