Migrate to Avalonia 12 and Plugin SDK v5

Upgrade project to the Avalonia 12 baseline and Plugin SDK v5: centralize Avalonia packages, remove legacy WebView.Avalonia usage (use NativeWebView/WebView2 EnvironmentRequested), and update Fluent/Material icon/package usages. Bump multiple package/project versions to 5.0.0 and Avalonia 12.0.1, update plugin template and README/docs to SDK v5, and add PLUGIN_SDK_V5_MIGRATION.md.

Also fix runtime/behavior bugs: make DataLocationResolver use a fixed bootstrap launcher data path and avoid recursive ResolveDataRoot; add legacy-state handling and extraction in OobeStateService; and update component settings tests to reflect migrated storage (DB/backup) and reset cache for test reloads. Various csproj, tests, and docs updated to reflect the migration and ensure build/test compatibility.

docs/Plugins develop/01-快速开始/02-三分钟创建第一个插件.md

@@ -40,7 +40,7 @@ cd MyFirstPlugin
   "description": "这是一个测试插件",
   "author": "你的名字",
   "version": "1.0.0",
-  "apiVersion": "4.0.1",
+  "apiVersion": "5.0.0",
   "entranceAssembly": "MyFirstPlugin.dll",
   "sharedContracts": []
 }

docs/Plugins develop/01-快速开始/03-插件项目结构详解.md

@@ -35,7 +35,7 @@ MyPlugin/
   "description": "这是一个示例插件",
   "author": "作者名称",
   "version": "1.0.0",
-  "apiVersion": "4.0.1",
+  "apiVersion": "5.0.0",
   "entranceAssembly": "MyPlugin.dll",
   "sharedContracts": [],
   "website": "https://example.com",
@@ -53,7 +53,7 @@ MyPlugin/
 | `description` | ✅ | 简短描述 | `显示实时天气信息` |
 | `author` | ✅ | 作者名称 | `张三` |
 | `version` | ✅ | 版本号（语义化版本） | `1.0.0` |
-| `apiVersion` | ✅ | SDK API 版本 | `4.0.1` |
+| `apiVersion` | ✅ | SDK API 版本 | `5.0.0` |
 | `entranceAssembly` | ✅ | 入口程序集文件名 | `MyPlugin.dll` |
 | `sharedContracts` | ✅ | 共享契约类型列表 | `[]` |
 | `website` | ❌ | 项目网站 | `https://github.com/...` |
@@ -74,7 +74,7 @@ MyPlugin/
 
 ⚠️ **apiVersion 字段规则：**
 - 必须与引用的 SDK 版本兼容
-- 当前最新版本：`4.0.1`
+- 当前最新版本：`5.0.0`
 - 不兼容时宿主将拒绝加载插件
 
 ---
@@ -96,7 +96,7 @@ MyPlugin/
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="LanMountainDesktop.PluginSdk" Version="4.0.1" />
+    <PackageReference Include="LanMountainDesktop.PluginSdk" Version="5.0.0" />
   </ItemGroup>
 
   <ItemGroup>
@@ -122,7 +122,7 @@ MyPlugin/
 ### SDK 引用
 
 ```xml
-<PackageReference Include="LanMountainDesktop.PluginSdk" Version="4.0.1" />
+<PackageReference Include="LanMountainDesktop.PluginSdk" Version="5.0.0" />
 ```
 
 ⚠️ **版本必须匹配：**

docs/Plugins develop/02-核心概念与原理/01-插件生命周期.md

@@ -213,7 +213,7 @@ public override void Initialize(HostBuilderContext context, IServiceCollection s
 - 关闭阑山桌面
 
 **当前限制：**
-- SDK v4 暂无显式的卸载回调方法
+- SDK v5 暂无显式的卸载回调方法
 - 资源释放依赖 .NET 垃圾回收
 - 建议：
   - 使用 `IDisposable` 模式管理资源

docs/Plugins develop/07-发布与运营/01-插件打包规范.md

@@ -33,7 +33,7 @@ MyPlugin.laapp
   "description": "插件描述",
   "author": "作者名",
   "version": "1.0.0",
-  "apiVersion": "4.0.1",
+  "apiVersion": "5.0.0",
   "entranceAssembly": "MyPlugin.dll",
   "sharedContracts": []
 }
@@ -61,7 +61,7 @@ MyPlugin.laapp
   </PropertyGroup>
   
   <ItemGroup>
-    <PackageReference Include="LanMountainDesktop.PluginSdk" Version="4.0.1" />
+    <PackageReference Include="LanMountainDesktop.PluginSdk" Version="5.0.0" />
   </ItemGroup>
   
   <!-- 确保资源文件复制到输出目录 -->