feat: provider api_formats 可空继承、OpenAI 图片 edit/variation 与用量配额多项补强

- 鉴权: provider_api_keys.api_formats 改为可空，OAuth 托管 key 自动继承 provider endpoints 激活格式，相关 handler/测试同步更新
- 图片 planner: OpenAI 图片路由新增 edit/variation 操作并完善参数校验、响应合并与流式处理
- 用量: user me usage 返回区分 client_requested_stream/upstream_is_stream，前端 usage 列表筛选与展示增强
- 统计: stats_daily_model 新增 cache_creation_ephemeral_5m/1h tokens 字段与回填链路
- 配额/observability: quota repository 新增内存与 SQL 扩展，admin observability usage 字段扩充
- 其它: OAuth 导入/轮询收敛、provider 汇总与 pool admin 读写链路小修、新增 system_config 缓存与 provider template handler

Closes #318

Co-authored-by: Entropy.Xu <53283266+Entropy-Xu@users.noreply.github.com>

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

@@ -53,6 +53,11 @@ pub trait ProviderQuotaReadRepository: Send + Sync {
         &self,
         provider_id: &str,
     ) -> Result<Option<StoredProviderQuotaSnapshot>, crate::DataLayerError>;
+
+    async fn find_by_provider_ids(
+        &self,
+        provider_ids: &[String],
+    ) -> Result<Vec<StoredProviderQuotaSnapshot>, crate::DataLayerError>;
 }
 
 #[async_trait]