feat: AgendaSection todos JSON 파싱 로직 추가

- ObjectMapper를 사용하여 todos JSON 문자열을 파싱
- TodoJson DTO 클래스 추가
- parseTodosJson() 메서드 구현
- MeetingStatisticsResponse에서 실제 Todo 개수 계산
- 에러 처리 로직 추가 (파싱 실패 시 빈 리스트 반환)

JSON 구조: [{title, assignee, dueDate, description, priority}]

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

meeting/src/main/java/com/unicorn/hgzero/meeting/infra/controller/MeetingAiController.java

@@ -1,5 +1,7 @@
 package com.unicorn.hgzero.meeting.infra.controller;
 
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import com.unicorn.hgzero.common.dto.ApiResponse;
 import com.unicorn.hgzero.meeting.biz.domain.AgendaSection;
 import com.unicorn.hgzero.meeting.biz.domain.Meeting;
@@ -19,6 +21,7 @@ import lombok.extern.slf4j.Slf4j;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -36,6 +39,7 @@ public class MeetingAiController {
     private final MinutesService minutesService;
     private final AgendaSectionService agendaSectionService;
     private final MeetingService meetingService;
+    private final ObjectMapper objectMapper;
 
     @GetMapping("/{meetingId}/ai/participant-minutes")
     @Operation(
@@ -162,8 +166,10 @@ public class MeetingAiController {
     }
 
     private AgendaSectionResponse.AgendaSectionItem convertToAgendaSectionItem(AgendaSection section) {
-        // todos와 pendingItems는 JSON 문자열이므로 파싱 필요 (현재는 null로 처리)
-        List<AgendaSectionResponse.AgendaSectionItem.TodoItem> todos = null;
+        // todos JSON 파싱
+        List<AgendaSectionResponse.AgendaSectionItem.TodoItem> todos = parseTodosJson(section.getTodos());
+
+        // pendingItems는 사용하지 않으므로 null 처리
         List<String> pendingItems = null;
 
         return AgendaSectionResponse.AgendaSectionItem.builder()
@@ -180,12 +186,57 @@ public class MeetingAiController {
                 .build();
     }
 
+    /**
+     * todos JSON 문자열을 파싱하여 TodoItem 리스트로 변환
+     * JSON 구조: [{"title": "...", "assignee": "...", "dueDate": "...", "description": "...", "priority": "..."}]
+     */
+    private List<AgendaSectionResponse.AgendaSectionItem.TodoItem> parseTodosJson(String todosJson) {
+        if (todosJson == null || todosJson.trim().isEmpty()) {
+            return new ArrayList<>();
+        }
+
+        try {
+            List<TodoJson> todoJsonList = objectMapper.readValue(
+                todosJson,
+                new TypeReference<List<TodoJson>>() {}
+            );
+
+            return todoJsonList.stream()
+                    .map(json -> AgendaSectionResponse.AgendaSectionItem.TodoItem.builder()
+                            .title(json.getTitle())
+                            .assignee(json.getAssignee())
+                            .dueDate(json.getDueDate())
+                            .description(json.getDescription())
+                            .priority(json.getPriority())
+                            .build())
+                    .collect(Collectors.toList());
+
+        } catch (Exception e) {
+            log.error("Failed to parse todos JSON: {}", todosJson, e);
+            return new ArrayList<>();
+        }
+    }
+
+    /**
+     * JSON 파싱을 위한 임시 DTO
+     */
+    @lombok.Data
+    private static class TodoJson {
+        private String title;
+        private String assignee;
+        private String dueDate;
+        private String description;
+        private String priority;
+    }
+
     private MeetingStatisticsResponse buildMeetingStatistics(String meetingId) {
         Meeting meeting = meetingService.getMeeting(meetingId);
         List<AgendaSection> sections = agendaSectionService.getAgendaSectionsByMeetingId(meetingId);
 
-        // AI가 추출한 Todo 수 계산 (todos는 JSON 문자열이므로 현재는 0으로 처리)
-        int todoCount = 0;
+        // AI가 추출한 Todo 수 계산
+        int todoCount = sections.stream()
+                .mapToInt(s -> parseTodosJson(s.getTodos()).size())
+                .sum();
 
         // 회의 시간 계산
         Integer durationMinutes = null;