feat: 添加国际化支持，包含文化变更事件、资源提供者和本地化字符串结构

i18n/Aurora.I18N.Abstractions/CultureChangedEventArgs.cs

@@ -0,0 +1,15 @@
+using System.Globalization;
+
+namespace Aurora.I18N;
+
+/// <summary>
+/// 文化变更事件参数
+/// </summary>
+public sealed class CultureChangedEventArgs(CultureInfo oldCulture, CultureInfo newCulture) : EventArgs
+{
+    public CultureInfo OldCulture { get; }
+        = oldCulture ?? throw new ArgumentNullException(nameof(oldCulture));
+
+    public CultureInfo NewCulture { get; }
+        = newCulture ?? throw new ArgumentNullException(nameof(newCulture));
+}