fix: 租户端启动补齐字典与消息依赖

src/Modules/TakeoutSaaS.Module.Messaging/Extensions/MessagingServiceCollectionExtensions.cs

@@ -17,8 +17,17 @@ public static class MessagingServiceCollectionExtensions
     /// </summary>
     public static IServiceCollection AddMessagingModule(this IServiceCollection services, IConfiguration configuration)
     {
+        var rabbitMqSection = configuration.GetSection("RabbitMQ");
+        if (!rabbitMqSection.Exists())
+        {
+            services.AddSingleton<IMessagePublisher, NoOpMessagePublisher>();
+            services.AddSingleton<IMessageSubscriber, NoOpMessageSubscriber>();
+            return services;
+        }
+
+        // 1. (空行后) 存在 RabbitMQ 配置时才启用真实 MQ 能力（启动时验证配置完整性）
         services.AddOptions<RabbitMqOptions>()
-            .Bind(configuration.GetSection("RabbitMQ"))
+            .Bind(rabbitMqSection)
             .ValidateDataAnnotations()
             .ValidateOnStart();
 

src/Modules/TakeoutSaaS.Module.Messaging/Services/NoOpMessagePublisher.cs

@@ -0,0 +1,21 @@
+using Microsoft.Extensions.Logging;
+using TakeoutSaaS.Module.Messaging.Abstractions;
+
+namespace TakeoutSaaS.Module.Messaging.Services;
+
+/// <summary>
+/// 空实现消息发布器：用于未配置 RabbitMQ 的开发/测试场景，避免启动依赖外部 MQ。
+/// </summary>
+public sealed class NoOpMessagePublisher(ILogger<NoOpMessagePublisher> logger) : IMessagePublisher
+{
+    /// <inheritdoc />
+    public Task PublishAsync<T>(string routingKey, T message, CancellationToken cancellationToken = default)
+    {
+        logger.LogDebug(
+            "未配置 RabbitMQ，已跳过消息发布：RoutingKey={RoutingKey} MessageType={MessageType}",
+            routingKey,
+            typeof(T).FullName ?? typeof(T).Name);
+        return Task.CompletedTask;
+    }
+}
+

src/Modules/TakeoutSaaS.Module.Messaging/Services/NoOpMessageSubscriber.cs

@@ -0,0 +1,25 @@
+using Microsoft.Extensions.Logging;
+using TakeoutSaaS.Module.Messaging.Abstractions;
+
+namespace TakeoutSaaS.Module.Messaging.Services;
+
+/// <summary>
+/// 空实现消息订阅器：用于未配置 RabbitMQ 的开发/测试场景。
+/// </summary>
+public sealed class NoOpMessageSubscriber(ILogger<NoOpMessageSubscriber> logger) : IMessageSubscriber
+{
+    /// <inheritdoc />
+    public Task SubscribeAsync<T>(string queue, string routingKey, Func<T, CancellationToken, Task<bool>> handler, CancellationToken cancellationToken = default)
+    {
+        logger.LogWarning("未配置 RabbitMQ，消息订阅被禁用：Queue={Queue} RoutingKey={RoutingKey}", queue, routingKey);
+        return Task.CompletedTask;
+    }
+
+    // 1. (空行后) 释放资源（NoOp 实现无实际资源）
+    /// <inheritdoc />
+    public ValueTask DisposeAsync()
+    {
+        logger.LogDebug("NoOpMessageSubscriber 已释放。");
+        return ValueTask.CompletedTask;
+    }
+}