feat: 重构数据库迁移架构，支持多数据库提供程序 (SQLite/SQLServer/PostgreSQL/MySQL)

- 将迁移文件按数据库类型分目录存放 (Migrations/SQLite, MySQL, PostgreSQL, SqlServer)
- 新增各数据库提供程序的 DesignTimeDbContextFactory，支持 --provider 参数切换
- 新增 ProviderAppDataContexts，定义各数据库对应的 AppDataContext 子类
- DatabaseExtensions 增加 AddProviderAppDataContext 方法，按配置自动注册对应 DbContext
- 修正 MySQL 提供程序调用方式 (UseMySql -> UseMySQL)
- UserEntity 模型增加新字段
- 更新 add-migration.ps1

Avalonia-API/Avalonia-API.csproj

@@ -10,7 +10,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="10.0.5" />
     <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="10.0.5" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="10.0.0">
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="10.0.7">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>

Avalonia-API/appsettings.json

@@ -14,8 +14,8 @@
     "RefreshTokenDays": 30
   },
   "DatabaseConfiguration": {
-    "Provider": "SQLite",
-    "ConnectionString": "Data Source=avalonia-api.db",
+    "Provider": "MySQL",
+    "ConnectionString": "Server=127.0.0.1;Port=3306;Database=avalonia-api;Uid=root;Pwd=123456;Max Pool Size=100;Min Pool Size=5;AllowZeroDateTime=True;AllowLoadLocalInfile=true;SslMode=Required",
     "AutoMigrate": true,
     "RecreateDatabase": false,
     "EnableDetailedLog": false,