feat(content): 资讯增删改 + C端资讯中心(类别)端点

- ContentRepository：+update(部分字段)/get/delete
- schemas.operator：+ContentUpdateRequest(全可选)
- rbac_operator：+PUT/DELETE /admin/content/{id}(action:content.manage+审计)
- rbac_opc：+GET /opc/content?type=policy|news|skill|dynamic(仅published)、/opc/content/{id}(详情)
- 类别字典 policy/news/skill/dynamic

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

app/api/schemas/operator.py

@@ -94,6 +94,15 @@ class ContentStatusRequest(BaseModel):
     status: str  # published/offline/draft
 
 
+class ContentUpdateRequest(BaseModel):
+    """内容更新（字段全可选，仅更新传入项）。"""
+    type: str | None = None       # policy/news/skill/dynamic
+    title: str | None = None
+    summary: str | None = None
+    body: str | None = None
+    status: str | None = None
+
+
 
 class ConfigUpdateRequest(BaseModel):
     value: str