feat: 新增租户上下文作用域扩展

src/Core/TakeoutSaaS.Shared.Abstractions/Tenancy/TenantContextAccessorExtensions.cs

@@ -0,0 +1,34 @@
+namespace TakeoutSaaS.Shared.Abstractions.Tenancy;
+
+/// <summary>
+/// <see cref="ITenantContextAccessor"/> 扩展方法。
+/// </summary>
+public static class TenantContextAccessorExtensions
+{
+    /// <summary>
+    /// 进入指定租户上下文作用域，释放后自动恢复之前的上下文。
+    /// </summary>
+    /// <param name="accessor">租户上下文访问器。</param>
+    /// <param name="tenantId">租户 ID。</param>
+    /// <param name="source">上下文来源标识（例如 scheduler、seed、admin）。</param>
+    /// <param name="tenantCode">租户编码（可选）。</param>
+    /// <returns>作用域对象。</returns>
+    public static IDisposable EnterTenantScope(
+        this ITenantContextAccessor accessor,
+        long tenantId,
+        string source,
+        string? tenantCode = null)
+    {
+        var previous = accessor.Current;
+        accessor.Current = new TenantContext(tenantId, tenantCode, source);
+        return new TenantContextScope(accessor, previous);
+    }
+
+    private sealed class TenantContextScope(ITenantContextAccessor accessor, TenantContext? previous) : IDisposable
+    {
+        public void Dispose()
+        {
+            accessor.Current = previous;
+        }
+    }
+}