持久化 provider key 使用统计并移除 usage 汇总覆盖 (#313)

* 持久化 provider key 使用统计并移除 usage 汇总覆盖

- 在 usage upsert 时按请求前后差值同步 provider_api_keys 统计
- 增加基于保留 usage 记录的 provider key 统计重建能力
- 号池管理列表直接读取 provider_api_keys 统计字段

* fix: harden provider key usage stats sync

---------

Co-authored-by: fawney19 <elky0401@gmail.com>

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

@@ -3,6 +3,14 @@ use aether_data_contracts::repository::{candidates, usage};
 use usage::{StoredUsageDailySummary, UsageDailyHeatmapQuery};
 
 impl AppState {
+    #[allow(dead_code)]
+    pub(crate) async fn rebuild_provider_api_key_usage_stats(&self) -> Result<u64, GatewayError> {
+        self.data
+            .rebuild_provider_api_key_usage_stats()
+            .await
+            .map_err(|err| GatewayError::Internal(err.to_string()))
+    }
+
     pub(crate) async fn read_request_candidates_by_request_id(
         &self,
         request_id: &str,