持久层重构为独立 MiGu.DB 工程并优化集成

- 新增 MiGu.DB 项目，迁移所有领域实体与枚举，统一模型约定
- 实现 Entity/Repository/UoW/Provider/Exception 等接口与实现
- 支持数据修补机制，完善 Sqlite 初始迁移与数据库管理
- Server 侧移除 EF Core 相关，依赖 MiGu.DB，PlatformPersistence 适配
- 业务服务注入 UoW/Repository，状态字段统一用 enum 及辅助类
- 统一异常处理，Controller 映射 HTTP 状态码
- 配置项与文档补充数据库启动、SchemaMode、迁移说明
- 新增 GlobalUsings.Db.cs、WmsStatusAliases.cs 简化类型引用
- 新增 HttpActorContextMiddleware 支持操作者上下文一致性
- 新增 MiGuDbContextModelSnapshot 追踪数据库结构
- 优化代码结构，解耦领域与持久层，提升扩展性与安全性

MiGu.Server/Persistence/HttpActorContextMiddleware.cs

@@ -0,0 +1,36 @@
+using Microsoft.AspNetCore.Http;
+using MiGu.DB.Abstractions.Runtime;
+using MiGu.DB.Kernel.Conventions;
+
+namespace MiGu.Server.Persistence;
+
+/// <summary>从 JWT Claims 解析当前操作者，写入 IActorContextAccessor。</summary>
+public sealed class HttpActorContextMiddleware
+{
+    private readonly RequestDelegate _next;
+
+    public HttpActorContextMiddleware(RequestDelegate next) => _next = next;
+
+    public async Task InvokeAsync(HttpContext http, IActorContextAccessor actors)
+    {
+        var name = http.User?.Identity?.Name
+            ?? http.User?.FindFirst("sub")?.Value
+            ?? http.User?.FindFirst("unique_name")?.Value
+            ?? "system";
+        actors.Current = new HttpActorContext(name);
+        try
+        {
+            await _next(http);
+        }
+        finally
+        {
+            actors.Current = SystemActorContext.Instance;
+        }
+    }
+
+    private sealed class HttpActorContext : IActorContext
+    {
+        public HttpActorContext(string name) => Name = name;
+        public string Name { get; }
+    }
+}