perf(usage): heatmap 改为数据库端按天聚合查询

将 admin 和 user heatmap 从逐条加载 usage audit 记录后在应用层聚合,
改为通过 SQL GROUP BY DATE 在数据库端直接按天汇总, 大幅减少数据传输量。

新增 UsageDailyHeatmapQuery / StoredUsageDailySummary 类型,
在 trait、SQL、内存实现中均补齐 summarize_usage_daily_heatmap 方法。

同时优化 docker-compose: postgres 增加空闲事务超时与 keepalive 参数,
gateway 增加健康检查配置。

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

@@ -1,5 +1,6 @@
 use crate::{AppState, GatewayError};
 use aether_data_contracts::repository::{candidates, usage};
+use usage::{StoredUsageDailySummary, UsageDailyHeatmapQuery};
 
 impl AppState {
     pub(crate) async fn read_request_candidates_by_request_id(
@@ -44,6 +45,16 @@ impl AppState {
             .map_err(|err| GatewayError::Internal(err.to_string()))
     }
 
+    pub(crate) async fn summarize_usage_daily_heatmap(
+        &self,
+        query: &UsageDailyHeatmapQuery,
+    ) -> Result<Vec<StoredUsageDailySummary>, GatewayError> {
+        self.data
+            .summarize_usage_daily_heatmap(query)
+            .await
+            .map_err(|err| GatewayError::Internal(err.to_string()))
+    }
+
     pub(crate) async fn list_recent_usage_audits(
         &self,
         user_id: Option<&str>,