fix: RabbitMQ 연결 실패 시 앱 크래시 방지 (#124)

- StartAsync에서 throw 제거, LogWarning으로 변경
- InitializeAsync 메서드 분리 (재시도 가능)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

SPMS.Infrastructure/Messaging/RabbitMQInitializer.cs

@@ -26,66 +26,67 @@ public class RabbitMQInitializer : IHostedService
     {
         try
         {
-            await using var channel = await _connection.CreateChannelAsync(cancellationToken);
-
-            // Exchange 선언: Direct, Durable
-            await channel.ExchangeDeclareAsync(
-                exchange: _settings.Exchange,
-                type: ExchangeType.Direct,
-                durable: true,
-                autoDelete: false,
-                arguments: null,
-                cancellationToken: cancellationToken);
-
-            _logger.LogInformation("Exchange 선언 완료: {Exchange}", _settings.Exchange);
-
-            var queueArgs = new Dictionary<string, object?>
-            {
-                { "x-message-ttl", _settings.MessageTtl }
-            };
-
-            // Push Queue 선언
-            await channel.QueueDeclareAsync(
-                queue: _settings.PushQueue,
-                durable: true,
-                exclusive: false,
-                autoDelete: false,
-                arguments: queueArgs,
-                cancellationToken: cancellationToken);
-
-            await channel.QueueBindAsync(
-                queue: _settings.PushQueue,
-                exchange: _settings.Exchange,
-                routingKey: "push",
-                cancellationToken: cancellationToken);
-
-            _logger.LogInformation("Queue 선언 및 바인딩 완료: {Queue} → {Exchange} (routing_key: push)",
-                _settings.PushQueue, _settings.Exchange);
-
-            // Schedule Queue 선언
-            await channel.QueueDeclareAsync(
-                queue: _settings.ScheduleQueue,
-                durable: true,
-                exclusive: false,
-                autoDelete: false,
-                arguments: queueArgs,
-                cancellationToken: cancellationToken);
-
-            await channel.QueueBindAsync(
-                queue: _settings.ScheduleQueue,
-                exchange: _settings.Exchange,
-                routingKey: "schedule",
-                cancellationToken: cancellationToken);
-
-            _logger.LogInformation("Queue 선언 및 바인딩 완료: {Queue} → {Exchange} (routing_key: schedule)",
-                _settings.ScheduleQueue, _settings.Exchange);
+            await InitializeAsync(cancellationToken);
         }
         catch (Exception ex)
         {
-            _logger.LogError(ex, "RabbitMQ Exchange/Queue 초기화 실패");
-            throw;
+            _logger.LogWarning(ex, "RabbitMQ 초기화 실패 — 서버는 계속 실행됩니다. 메시지 발송 시 재연결을 시도합니다.");
         }
     }
 
+    public async Task InitializeAsync(CancellationToken cancellationToken)
+    {
+        await using var channel = await _connection.CreateChannelAsync(cancellationToken);
+
+        await channel.ExchangeDeclareAsync(
+            exchange: _settings.Exchange,
+            type: ExchangeType.Direct,
+            durable: true,
+            autoDelete: false,
+            arguments: null,
+            cancellationToken: cancellationToken);
+
+        _logger.LogInformation("Exchange 선언 완료: {Exchange}", _settings.Exchange);
+
+        var queueArgs = new Dictionary<string, object?>
+        {
+            { "x-message-ttl", _settings.MessageTtl }
+        };
+
+        await channel.QueueDeclareAsync(
+            queue: _settings.PushQueue,
+            durable: true,
+            exclusive: false,
+            autoDelete: false,
+            arguments: queueArgs,
+            cancellationToken: cancellationToken);
+
+        await channel.QueueBindAsync(
+            queue: _settings.PushQueue,
+            exchange: _settings.Exchange,
+            routingKey: "push",
+            cancellationToken: cancellationToken);
+
+        _logger.LogInformation("Queue 선언 및 바인딩 완료: {Queue} → {Exchange} (routing_key: push)",
+            _settings.PushQueue, _settings.Exchange);
+
+        await channel.QueueDeclareAsync(
+            queue: _settings.ScheduleQueue,
+            durable: true,
+            exclusive: false,
+            autoDelete: false,
+            arguments: queueArgs,
+            cancellationToken: cancellationToken);
+
+        await channel.QueueBindAsync(
+            queue: _settings.ScheduleQueue,
+            exchange: _settings.Exchange,
+            routingKey: "schedule",
+            cancellationToken: cancellationToken);
+
+        _logger.LogInformation("Queue 선언 및 바인딩 완료: {Queue} → {Exchange} (routing_key: schedule)",
+            _settings.ScheduleQueue, _settings.Exchange);
+    }
+
     public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
 }