This PR improves key handling on Windows by moving the
`TranslateMessage` call from the message loop to after we handled
`WM_KEYDOWN`. This brings Windows behavior more in line with macOS and
gives us finer control over key events. As a result, Vim keybindings now
work properly even when an IME is active. The trade-off is that it might
introduce a slight delay in text input.


Release Notes:

- N/A