refactor: 重构活跃请求查询逻辑到 UsageService

- 在 UsageService 新增 get_active_requests 方法，统一处理活跃请求查询
- 支持自动清理超时的 pending 请求（默认 5 分钟）
- admin 和 user 接口均复用该方法，减少重复代码
- 支持按 ID 列表查询或查询所有活跃请求

src/api/user_me/routes.py

@@ -662,60 +662,18 @@ class GetActiveRequestsAdapter(AuthenticatedApiAdapter):
     ids: Optional[str] = None
 
     async def handle(self, context):  # type: ignore[override]
+        from src.services.usage import UsageService
+
         db = context.db
         user = context.user
-
+        id_list = None
         if self.ids:
-            # 查询指定 ID 的请求状态（只能查询自己的）
             id_list = [id.strip() for id in self.ids.split(",") if id.strip()]
             if not id_list:
                 return {"requests": []}
 
-            records = (
-                db.query(
-                    Usage.id,
-                    Usage.status,
-                    Usage.input_tokens,
-                    Usage.output_tokens,
-                    Usage.total_cost_usd,
-                    Usage.response_time_ms,
-                )
-                .filter(Usage.id.in_(id_list), Usage.user_id == user.id)
-                .all()
-            )
-        else:
-            # 查询所有活跃请求（pending 或 streaming）
-            records = (
-                db.query(
-                    Usage.id,
-                    Usage.status,
-                    Usage.input_tokens,
-                    Usage.output_tokens,
-                    Usage.total_cost_usd,
-                    Usage.response_time_ms,
-                )
-                .filter(
-                    Usage.user_id == user.id,
-                    Usage.status.in_(["pending", "streaming"]),
-                )
-                .order_by(Usage.created_at.desc())
-                .limit(50)
-                .all()
-            )
-
-        return {
-            "requests": [
-                {
-                    "id": r.id,
-                    "status": r.status,
-                    "input_tokens": r.input_tokens,
-                    "output_tokens": r.output_tokens,
-                    "cost": float(r.total_cost_usd) if r.total_cost_usd else 0,
-                    "response_time_ms": r.response_time_ms,
-                }
-                for r in records
-            ]
-        }
+        requests = UsageService.get_active_requests(db=db, ids=id_list, user_id=user.id)
+        return {"requests": requests}
 
 
 class ListAvailableProvidersAdapter(AuthenticatedApiAdapter):