refactor(report): MonthlyReport AiChatOption reasoningEffort 변경

medium으로 변경

Author: coldsunn

src/main/java/com/devkor/ifive/nadab/domain/monthlyreport/infra/MonthlyReportLlmClient.java

@@ -31,7 +31,7 @@ public AiMonthlyReportResultDto generate(
 
         OpenAiChatOptions options = OpenAiChatOptions.builder()
                 .model(OpenAiApi.ChatModel.GPT_5_MINI)
-                .reasoningEffort("low")
+                .reasoningEffort("medium")
                 .temperature(1.0)
                 .build();