feat(admin): 将用户管理的用量统计改为全量累计口径 (#314)

- 新增按用户 ID 批量汇总 usage 的后端查询
- 在 /api/admin/users 中返回 request_count 和 total_tokens
- 移除用户管理页面额外的 usage 聚合请求
- 为管理端用户列表补充累计统计回归测试

apps/aether-gateway/src/data/state/runtime.rs

@@ -836,6 +836,21 @@ impl GatewayDataState {
         }
     }
 
+    pub(crate) async fn summarize_usage_totals_by_user_ids(
+        &self,
+        user_ids: &[String],
+    ) -> Result<Vec<aether_data_contracts::repository::usage::StoredUsageUserTotals>, DataLayerError>
+    {
+        match &self.usage_reader {
+            Some(repository) => {
+                repository
+                    .summarize_usage_totals_by_user_ids(user_ids)
+                    .await
+            }
+            None => Ok(Vec::new()),
+        }
+    }
+
     pub(crate) async fn summarize_usage_cache_hit_summary(
         &self,
         query: &aether_data_contracts::repository::usage::UsageCacheHitSummaryQuery,