Separate menu shortcut presentation from lookup identity. Store either a
normalized key equivalent or a physical keycode in a private hashable enum,
allowing Swift to synthesize equality and hashing instead of maintaining
parallel optional-key logic.
Assign display characters directly from KeyboardShortcut and remove unused
NSMenuItem and SwiftUI conversion helpers.
Translate printable physical keybindings through the current macOS
keyboard layout before assigning menu key equivalents. Previously these
bindings could not be represented because SwiftUI shortcuts are
character-based, so actions such as super+backquote had no native menu
shortcut.
Keep native keycodes as dispatch identity so translated display characters
do not change physical semantics or precedence over Unicode bindings.
Refresh shortcuts when the input source changes, and prevent AppKit from
transforming equivalents that are already localized.
