feat: 添加安全模块 + Dockerfile添加curl支持健康检查

主要更新:
- 新增 security/ 安全模块 (风险评估、威胁检测、蜜罐等)
- Dockerfile 添加 curl 以支持 Docker 健康检查
- 前端页面更新 (管理后台、用户端)
- 数据库迁移和 schema 更新
- 新增 kdocs 上传服务
- 添加安全相关测试用例

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

db/announcements.py

@@ -6,10 +6,12 @@ import db_pool
 from db.utils import get_cst_now_str
 
 
-def create_announcement(title, content, is_active=True):
+def create_announcement(title, content, image_url=None, is_active=True):
     """创建公告（默认启用；启用时会自动停用其他公告）"""
     title = (title or "").strip()
     content = (content or "").strip()
+    image_url = (image_url or "").strip()
+    image_url = image_url or None
     if not title or not content:
         return None
 
@@ -22,10 +24,10 @@ def create_announcement(title, content, is_active=True):
 
         cursor.execute(
             """
-            INSERT INTO announcements (title, content, is_active, created_at, updated_at)
-            VALUES (?, ?, ?, ?, ?)
+            INSERT INTO announcements (title, content, image_url, is_active, created_at, updated_at)
+            VALUES (?, ?, ?, ?, ?, ?)
             """,
-            (title, content, 1 if is_active else 0, cst_time, cst_time),
+            (title, content, image_url, 1 if is_active else 0, cst_time, cst_time),
         )
         conn.commit()
         return cursor.lastrowid
@@ -129,4 +131,3 @@ def dismiss_announcement_for_user(user_id, announcement_id):
         )
         conn.commit()
         return cursor.rowcount >= 0
-