Support keyboard shortcuts that work regardless of input language/layout

[nivedano]

Currently, keyboard shortcuts in Excalidraw (such as Ctrl+D for duplicate) only work when the English keyboard layout is active. When using another layout, these shortcuts do not function because the extension seems to check the character rather than the physical key.

Could you please consider implementing shortcut handling based on physical key codes (e.g., using event.code instead of event.key)? This would allow shortcuts to work regardless of the current input language, which is essential for multilingual users.

Alternatively, allowing users to customize shortcuts via VS Code settings would also solve this issue.

Thank you!