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。

crates/aether-data-contracts/src/repository/usage/mod.rs

@@ -3,6 +3,6 @@ mod types;
 pub use types::{
     parse_usage_body_ref, usage_body_ref, StoredProviderApiKeyUsageSummary,
     StoredProviderUsageSummary, StoredProviderUsageWindow, StoredRequestUsageAudit,
-    UpsertUsageRecord, UsageAuditListQuery, UsageBodyField, UsageReadRepository, UsageRepository,
-    UsageWriteRepository,
+    StoredUsageDailySummary, UpsertUsageRecord, UsageAuditListQuery, UsageBodyField,
+    UsageDailyHeatmapQuery, UsageReadRepository, UsageRepository, UsageWriteRepository,
 };

crates/aether-data-contracts/src/repository/usage/types.rs

@@ -482,6 +482,25 @@ pub struct UsageAuditListQuery {
     pub model: Option<String>,
 }
 
+#[derive(Debug, Clone, PartialEq, Default, serde::Serialize, serde::Deserialize)]
+pub struct UsageDailyHeatmapQuery {
+    pub created_from_unix_secs: u64,
+    pub user_id: Option<String>,
+    /// When true, exclude rows with status in ('pending', 'streaming') (admin heatmap).
+    /// When false, only include rows with billing_status = 'settled' and total_cost_usd > 0 (user heatmap).
+    pub admin_mode: bool,
+}
+
+#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+pub struct StoredUsageDailySummary {
+    /// Date as "YYYY-MM-DD"
+    pub date: String,
+    pub requests: u64,
+    pub total_tokens: u64,
+    pub total_cost_usd: f64,
+    pub actual_total_cost_usd: f64,
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 #[serde(rename_all = "snake_case")]
 pub enum UsageBodyField {
@@ -586,6 +605,11 @@ pub trait UsageReadRepository: Send + Sync {
         provider_id: &str,
         since_unix_secs: u64,
     ) -> Result<StoredProviderUsageSummary, crate::DataLayerError>;
+
+    async fn summarize_usage_daily_heatmap(
+        &self,
+        query: &UsageDailyHeatmapQuery,
+    ) -> Result<Vec<StoredUsageDailySummary>, crate::DataLayerError>;
 }
 
 #[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]