feat.完善了时钟轻应用，为启动器提供了多语言支持

LanMountainDesktop.Launcher/Services/LanguagePreferenceService.cs

@@ -0,0 +1,56 @@
+using System.Globalization;
+using System.Text.Json.Nodes;
+
+namespace LanMountainDesktop.Launcher.Services;
+
+internal static class LanguagePreferenceService
+{
+    public static string ResolveLanguageCode(string appRoot)
+    {
+        try
+        {
+            var dataLocationResolver = new DataLocationResolver(appRoot);
+            var settingsPath = HostAppSettingsOobeMerger.GetSettingsFilePath(dataLocationResolver.ResolveDataRoot());
+            if (!File.Exists(settingsPath))
+            {
+                return "zh-CN";
+            }
+
+            var root = JsonNode.Parse(File.ReadAllText(settingsPath))?.AsObject();
+            if (root is not null &&
+                root.TryGetPropertyValue("LanguageCode", out var node) &&
+                node is JsonValue value &&
+                value.TryGetValue<string>(out var code) &&
+                !string.IsNullOrWhiteSpace(code))
+            {
+                return NormalizeLanguageCode(code);
+            }
+        }
+        catch
+        {
+        }
+
+        return "zh-CN";
+    }
+
+    public static void ApplyLanguage(string languageCode)
+    {
+        var normalized = NormalizeLanguageCode(languageCode);
+        var culture = CultureInfo.GetCultureInfo(normalized);
+        CultureInfo.DefaultThreadCurrentCulture = culture;
+        CultureInfo.DefaultThreadCurrentUICulture = culture;
+        Thread.CurrentThread.CurrentCulture = culture;
+        Thread.CurrentThread.CurrentUICulture = culture;
+    }
+
+    private static string NormalizeLanguageCode(string code)
+    {
+        return code.ToLowerInvariant() switch
+        {
+            "en-us" or "en" => "en-US",
+            "ja-jp" or "ja" => "ja-JP",
+            "ko-kr" or "ko" => "ko-KR",
+            _ => "zh-CN"
+        };
+    }
+}