Fixes #4878 - Use first unbound F-key for UICatalog StatusBar toggle instead of hardcoded F10

[Copilot]

Fixes

• Fixes F10 StatusBar shortcut conflicts with menu toggle, does not work #4878

UICatalog's StatusBar "Show/Hide" shortcut was hardcoded to F10, which now conflicts with MenuBar.DefaultKey (F10 toggles the menu bar). Pressing F10 opens the menu instead of toggling the status bar.

Proposed Changes/Todos

• Add GetFirstUnboundFKey() to UICatalogRunnable that scans F1–F12 and returns the first key not bound in:
  • Application.KeyBindings (catches F5/Refresh, F6/NextTabGroup, etc.)
  • MenuBar.DefaultKey (F10) and PopoverMenu.DefaultKey (Shift+F10)
  • MenuBar menu items via GetMenuItemsWith() (catches F1/Documentation, F2/README)
• Replace Key.F10 with GetFirstUnboundFKey() in CreateStatusBar()

With the current UICatalog config, this resolves to F3.

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[Copilot]

Pull request overview

Updates UICatalog’s StatusBar “Show/Hide” shortcut to avoid the F10 conflict with MenuBar.DefaultKey by selecting the first available unbound function key at runtime.

Changes:

• Added GetFirstUnboundFKey () to scan F1–F12 and pick the first key not currently bound at the Application/Menu level.
• Replaced the hardcoded Key.F10 StatusBar toggle with the dynamically selected key.

Comments suppressed due to low confidence (1)

Examples/UICatalog/UICatalogRunnable.cs:781

• GetFirstUnboundFKey() is called before the StatusBar’s other shortcuts are created, but CreateStatusBar() later hard-binds F7 (force16ColorsShortcut). If F1–F6 ever become bound, this helper can return F7, creating a duplicate/conflicting shortcut key in the same StatusBar (and potentially an app-level binding because BindKeyToApplication=true on the F7 shortcut). Consider excluding keys that this status bar reserves (e.g., F7) or computing the unbound key after assembling all shortcuts.

        _shVersion = new Shortcut { Title = "Version Info", CanFocus = false };

        Shortcut statusBarShortcut = new () { Key = GetFirstUnboundFKey (), Title = "Show/Hide Status Bar", CanFocus = false, Action = () => ShowStatusBar = !ShowStatusBar };

        _force16ColorsShortcutCb = new CheckBox
        {
            Title = "16 color mode", Value = Driver.Force16Colors ? CheckState.Checked : CheckState.UnChecked, CanFocus = true
        };

        Shortcut force16ColorsShortcut = new ()
        {
            CanFocus = false,
            CommandView = _force16ColorsShortcutCb,
            HelpText = "",
            BindKeyToApplication = true,
            Key = Key.F7,
            Action = () =>