feat(gateway/data): 新增 usage 关键词搜索、缓存命中摘要、结算成本摘要及 dashboard 聚合查询能力

- 新增 UsageAuditKeywordSearchQuery，支持多关键词、用户名、API Key 交叉过滤
- 新增 UsageCacheHitSummaryQuery/StoredUsageCacheHitSummary，统计请求缓存命中率
- 新增 UsageSettledCostSummaryQuery/StoredUsageSettledCostSummary，汇总结算成本
- 新增 UsageDashboardSummaryQuery、UsageBreakdownSummaryQuery 等 dashboard 聚合类型
- SQL 层实现对应查询方法，含 list_by_ids、list_usage_audits_by_keyword_search、count_usage_audits_by_keyword_search
- 将上述能力通过 GatewayDataState / AdminAppState 暴露给 handler 层
- user_me_usage 及 dashboard_filters 切换为新查询接口，移除旧的内存过滤逻辑
- 同步更新 memory 层及测试

apps/aether-gateway/src/tests/control/admin/stats.rs

@@ -196,6 +196,15 @@ impl AuthApiKeyReadRepository for PartialListAuthApiKeyRepository {
         self.lookup.list_export_api_keys_by_ids(api_key_ids).await
     }
 
+    async fn list_export_api_keys_by_name_search(
+        &self,
+        name_search: &str,
+    ) -> Result<Vec<StoredAuthApiKeyExportRecord>, aether_data::DataLayerError> {
+        self.lookup
+            .list_export_api_keys_by_name_search(name_search)
+            .await
+    }
+
     async fn list_export_standalone_api_keys_page(
         &self,
         query: &StandaloneApiKeyExportListQuery,