fix(#693 app): 修复开发者模式下添加插件失败的问题

MSIX 安装目录（C:\Program Files\WindowsApps\...）是只读的，
而插件 XAML 热重载暂存目录 HotReloadRoot 之前放在 AppContext.BaseDirectory 下，
导致 PrepareResourceRoot 创建目录时抛出 UnauthorizedAccessException。
改为使用 AppStoragePaths.LocalDataPath（已正确处理 MSIX/便携/无包身份三种情况）。

Author: GoldenPotato137

.kilocode/rules/project-info-galgamemanager.md

@@ -1,4 +1,4 @@
-# GalgameManager Client (PotatoVN) - Detailed Knowledge Base
+# GalgameManager Client (PotatoVN) - Detailed Knowledge Base
 
 > After finishing editing, please remember to run GalgameManager.Test to ensure no tests are broken.
 >
@@ -169,7 +169,7 @@ This section highlights important files and directories specific to the client a
         *   All source services implement `IGalgameSourceService` interface which defines standard operations like `SaveMetaAsync`, `LoadMetaAsync`, `RemoveMetaAsync` for meta information management.
  *   **`Helpers/`**: Contains utility classes and extension methods that provide common, reusable functions (e.g., file I/O helpers, string manipulation, UI helpers).
      *   `VisibilityHelper.cs`: Provides converters for XAML bindings, e.g., converting a string's null/empty status to a `Visibility` value.
-     *   `GalgameManager/Services/PluginService/PluginXamlHost.cs`: Bridges dynamically loaded plugin assemblies into the host app's WinUI XAML system by loading plugin PRI resources and registering plugin `IXamlMetadataProvider` implementations before plugin UI is initialized.
+     *   `GalgameManager/Services/PluginService/PluginXamlHost.cs`: Bridges dynamically loaded plugin assemblies into the host app's WinUI XAML system by loading plugin PRI resources and registering plugin `IXamlMetadataProvider` implementations before plugin UI is initialized. Its dev-plugin hot-reload staging directory (`HotReloadRoot`) must live under `AppStoragePaths.LocalDataPath`, never `AppContext.BaseDirectory`: for MSIX installs the base directory is the read-only `C:\Program Files\WindowsApps\...` folder, so writing there throws `UnauthorizedAccessException` (issue #693). In general, never write runtime files under `AppContext.BaseDirectory`; use `AppStoragePaths.LocalDataPath`/`TempPath` (they handle MSIX, portable, and unpackaged cases).
     *   **`Helpers/Phrase/`**: Contains the mixed phraser system for aggregating game information from multiple sources:
         *   `MixedPhraser.cs`: The main mixed phraser implementation that combines data from multiple game information sources (Bangumi, VNDB, Ymgal, Steam, Hikarinagi). It supports selective enabling/disabling of individual phrasers through the `MixedPhraserEnabled` configuration. `GetGalgameInfo` waits on all parallel source tasks with a unified soft timeout (`TimeoutSeconds`); incomplete/faulted sources are dropped before merge.
         *   `VndbPhraser.cs`: VNDB queries that use the `search` filter must sort by `searchrank`; ID-based queries should keep their native ordering. API calls that may be throttled should use the shared retry wrapper so a retry preserves the original query.

GalgameManager/Services/PluginService/PluginXamlHost.cs

@@ -12,7 +12,8 @@ namespace GalgameManager.Services;
 
 internal static class PluginXamlHost
 {
-    public static string HotReloadRoot => Path.Combine(AppContext.BaseDirectory, "_PluginXamlHotReload");
+    // MSIX 的安装目录是只读的，热重载暂存目录必须放在可写的应用数据目录下（见 issue #693）
+    public static string HotReloadRoot => Path.Combine(AppStoragePaths.LocalDataPath, "_PluginXamlHotReload");
     private static readonly object SyncRoot = new();
     private static readonly ConcurrentDictionary<string, PluginAssemblyRegistration> Registrations = new();