[GUI] Add live localization bindings and fill missing locales (#685)

src/SharpEmu.GUI/LocalizedChoice.cs

@@ -0,0 +1,61 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
+
+namespace SharpEmu.GUI;
+
+/// <summary>
+/// A stable settings value with a display label that can be refreshed when
+/// the active UI language changes.
+/// </summary>
+public sealed class LocalizedChoice : INotifyPropertyChanged
+{
+    private string _label;
+
+    private LocalizedChoice(string value, string label, string? localizationKey)
+    {
+        Value = value;
+        _label = label;
+        LocalizationKey = localizationKey;
+    }
+
+    public string Value { get; }
+
+    public string Label
+    {
+        get => _label;
+        private set
+        {
+            if (_label == value)
+            {
+                return;
+            }
+
+            _label = value;
+            OnPropertyChanged();
+        }
+    }
+
+    private string? LocalizationKey { get; }
+
+    public event PropertyChangedEventHandler? PropertyChanged;
+
+    public static LocalizedChoice FromKey(string value, string localizationKey) =>
+        new(value, localizationKey, localizationKey);
+
+    public static LocalizedChoice Literal(string value, string label) =>
+        new(value, label, null);
+
+    public void Refresh(Localization localization)
+    {
+        if (LocalizationKey is { } key)
+        {
+            Label = localization.Get(key);
+        }
+    }
+
+    private void OnPropertyChanged([CallerMemberName] string? propertyName = null) =>
+        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+}