feat: 添加便携模式和打包脚本，精简打包大小

AppSettings.cs

@@ -11,7 +11,7 @@ namespace TimerApp
         public int IdleThresholdSeconds { get; set; } = 30;
         public bool IsDarkMode { get; set; } = true;
 
-        private static string LegacyConfigPath => Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "settings.json");
+        private static string LegacyConfigPath => Path.Combine(AppContext.BaseDirectory, "settings.json");
 
         private static string ConfigPath
         {
@@ -22,11 +22,22 @@ namespace TimerApp
             }
         }
 
+        private static string EffectiveConfigPath => PortableMode.IsPortable ? LegacyConfigPath : ConfigPath;
+
         public static AppSettings Load()
         {
             try
             {
-                string path = File.Exists(ConfigPath) ? ConfigPath : LegacyConfigPath;
+                string path;
+                if (PortableMode.IsPortable)
+                {
+                    path = LegacyConfigPath;
+                }
+                else
+                {
+                    path = File.Exists(ConfigPath) ? ConfigPath : LegacyConfigPath;
+                }
+
                 if (File.Exists(path))
                 {
                     string json = File.ReadAllText(path);
@@ -44,9 +55,12 @@ namespace TimerApp
         {
             try
             {
-                Directory.CreateDirectory(Path.GetDirectoryName(ConfigPath)!);
+                string path = EffectiveConfigPath;
+                string? dir = Path.GetDirectoryName(path);
+                if (!string.IsNullOrWhiteSpace(dir))
+                    Directory.CreateDirectory(dir);
                 string json = JsonSerializer.Serialize(this, new JsonSerializerOptions { WriteIndented = true });
-                File.WriteAllText(ConfigPath, json);
+                File.WriteAllText(path, json);
             }
             catch
             {