feat: 数据源统一与前端预览修复

=== 后端核心 ===
- db_helper: 统一数据库访问抽象层
- system.py API:
  * 参数绑定修复: 使用 Body(embed=True) 接收 JSON
  * 添加请求日志记录
- sync.py: 仅导出 DB→JSON（备份）

=== 合规与流水线 ===
- compliance_checker: 标签检测优化（仅检查容器，避免正文误判）
- 所有脚本（creator/collector/writer/outline/research等）统一使用数据库

=== 前端改版 ===
- topics.html:
  * 创作/优化 API 路径修正
  * 预览弹窗重设计：多平台并行加载、富文本显示、单复制按钮
  * 状态中文映射（getStatusLabel）
  * 认证检查
- 所有 HTML 静态资源路径修复（移除 /static 前缀）

=== 数据一致性 ===
- 数据库状态统一为英文（pending/review/ready/published）
- 前端显示中文化映射

已测试 A03 流水线完整通过。

scripts/collector.py

@@ -41,6 +41,7 @@ logging.basicConfig(
 )
 logger = logging.getLogger(__name__)
 
+
 @dataclass
 class SustainabilitySource:
     """可持续性信息源"""
@@ -511,33 +512,53 @@ class SustainabilityCollector:
         logger.info(f"保存了 {len(self.new_cases)} 个案例和 {len(self.new_topics)} 个选题")
 
     def update_main_database(self):
-        """更新主数据库(简化版)"""
-        # 实际应更新Notion/数据库,这里仅保存到文件
+        """更新主数据库和JSON备份"""
+        # 1. 更新案例库 (sustainability_cases.json)
         main_cases_file = DATA_DIR / "sustainability_cases.json"
-        main_topics_file = DATA_DIR / "sustainability_topics.json"
-
-        # 读取现有数据
         existing_cases = []
-        existing_topics = []
-
         if main_cases_file.exists():
-            with open(main_cases_file, 'r', encoding='utf-8') as f:
-                existing_cases = json.load(f)
-
-        if main_topics_file.exists():
-            with open(main_topics_file, 'r', encoding='utf-8') as f:
-                existing_topics = json.load(f)
-
-        # 合并新数据
+            try:
+                with open(main_cases_file, 'r', encoding='utf-8') as f:
+                    existing_cases = json.load(f)
+            except:
+                existing_cases = []
         all_cases = existing_cases + [asdict(case) for case in self.new_cases]
-        all_topics = existing_topics + [asdict(topic) for topic in self.new_topics]
-
-        # 保存(限制总数)
+        # 去重
+        seen = set()
+        unique_cases = []
+        for c in all_cases:
+            title = c.get('title', '').strip()
+            if title and title not in seen:
+                seen.add(title)
+                unique_cases.append(c)
+        unique_cases.sort(key=lambda x: x.get('collection_date', ''), reverse=True)
         with open(main_cases_file, 'w', encoding='utf-8') as f:
-            json.dump(all_cases[:100], f, ensure_ascii=False, indent=2)
+            json.dump(unique_cases[:200], f, ensure_ascii=False, indent=2)
+        logger.info(f"案例库更新: 总计 {len(unique_cases)} 个案例 (新增 {len(self.new_cases)})")
 
-        with open(main_topics_file, 'w', encoding='utf-8') as f:
-            json.dump(all_topics[:50], f, ensure_ascii=False, indent=2)
+        # 2. 更新选题数据库 (主数据源)
+        try:
+            from db_helper import save_topics_to_db
+            save_topics_to_db([asdict(topic) for topic in self.new_topics])
+            logger.info(f"选题数据库更新: 处理了 {len(self.new_topics)} 个选题")
+        except Exception as e:
+            logger.error(f"选题数据库保存失败: {e}")
+
+        # 3. 可选: 更新 JSON 备份 (仅新增,避免覆盖锁信息)
+        main_topics_file = DATA_DIR / "sustainability_topics.json"
+        try:
+            if main_topics_file.exists():
+                with open(main_topics_file, 'r', encoding='utf-8') as f:
+                    existing_topics = json.load(f)
+            else:
+                existing_topics = []
+            existing_ids = {t['id'] for t in existing_topics}
+            new_additions = [asdict(topic) for topic in self.new_topics if topic.id not in existing_ids]
+            existing_topics.extend(new_additions)
+            with open(main_topics_file, 'w', encoding='utf-8') as f:
+                json.dump(existing_topics, f, ensure_ascii=False, indent=2)
+        except Exception as e:
+            logger.error(f"JSON备份失败: {e}")
 
     def send_wecom_notification(self):
         """发送企业微信通知"""