Refactor: move hotkey display-string formatting onto HotKeyCombination

[GamalAnwar]

Summary

First PreferencesWindow slice. The shortcut row built its ⇧⌘1-style label inline in the view's displayText, including a 33-entry macOS keycode→label map (keyName) embedded in the SwiftUI struct.

This moves the formatting onto the model type, where modifierFlags already lives:

combo.displayString              // "⇧⌘1" — modifiers in ⌃⌥⇧⌘ order + key label
HotKeyCombination.keyName(23)    // "5"

The view keeps only its genuine UI states:

private var displayText: String {
    if isRecording { return "Press shortcut…" }
    if current.keyCode == 0 { return "None" }
    return current.displayString
}

Scope / safety

• Behavior-preserving — same symbols, same ordering, same Key<code> fallback.
• The keycode map's non-sequential quirk (kVK_ANSI_5 = 23, _6 = 22) is preserved and now has a regression test — this is the exact mapping that was previously swapped and mis-fired the recorder.
• event.modifierFlags uses in the live key-capture code are untouched (unrelated NSEvent accessor).

Tests

HotKeyCombinationDisplayTests (6 cases): command+shift digit, full ⌃⌥⇧⌘ ordering, non-sequential digit keycodes, unknown-keycode fallback, empty string for keyCode 0, and special-key labels (Space/Return/Esc).

🤖 Generated with Claude Code

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