feat: 增加案例/任务日志/LLM配置/系统配置管理功能\n\n- 扩展案例数据至30个\n- 新增Case, TaskLog, LLMConfig, SystemConfig的API路由\n- 完善initial_data导入脚本\n- 创建前端管理页面admin.html，支持完整增删改查\n- 更新导航菜单，增加系统管理入口

platform/backend/app/schemas.py

@@ -135,3 +135,69 @@ class AuditLogResponse(BaseModel):
 
     model_config = ConfigDict(from_attributes=True)
 
+
+# --- 案例库 Schema ---
+class CaseBase(BaseModel):
+    title: str
+    field: str
+    summary: str
+    key_metrics: Optional[str] = None
+    date: Optional[str] = None
+    source: str
+    source_url: Optional[str] = None
+    credibility_rating: Optional[str] = None
+    china_applicability: Optional[str] = None
+
+class CaseResponse(CaseBase):
+    id: int
+    created_at: Optional[datetime] = None
+    updated_at: Optional[datetime] = None
+
+    model_config = ConfigDict(from_attributes=True)
+
+
+# --- 任务日志 Schema ---
+class TaskLogBase(BaseModel):
+    task_name: str
+    topic_id: Optional[str] = None
+    status: str
+    message: Optional[str] = None
+    started_at: Optional[datetime] = None
+    finished_at: Optional[datetime] = None
+    duration_seconds: Optional[int] = None
+
+class TaskLogResponse(TaskLogBase):
+    id: int
+
+    model_config = ConfigDict(from_attributes=True)
+
+
+# --- LLM 配置 Schema ---
+class LLMConfigBase(BaseModel):
+    name: str
+    system_prompt: Optional[str] = None
+    user_prompt_template: str
+    temperature: float = 0.7
+    max_tokens: int = 2000
+    model: Optional[str] = None
+    is_active: bool = True
+
+class LLMConfigResponse(LLMConfigBase):
+    id: int
+    created_at: Optional[datetime] = None
+    updated_at: Optional[datetime] = None
+
+    model_config = ConfigDict(from_attributes=True)
+
+
+# --- 系统配置 Schema ---
+class SystemConfigBase(BaseModel):
+    key: str
+    value: Optional[str] = None
+    description: Optional[str] = None
+
+class SystemConfigResponse(SystemConfigBase):
+    updated_at: Optional[datetime] = None
+
+    model_config = ConfigDict(from_attributes=True)
+