refactor: 移除独立 hub/proxy/executor/gateway crate，统一为 gateway tunnel 架构

- 删除 aether-hub、aether-proxy 独立项目及其 Dockerfile/配置
- 删除 crates/aether-executor 和 crates/aether-gateway 全部模块
- 新增 apps/ 目录作为应用入口
- 将 hub 概念重构为 gateway tunnel transport
- 将 executor 重构为 execution runtime
- 新增 tunnel.rs 合约定义和 testkit tunnel/execution_runtime 模块
- 更新 Python 服务层和测试适配新架构命名

crates/aether-data/src/repository/usage/memory.rs

@@ -293,6 +293,33 @@ impl UsageWriteRepository for InMemoryUsageReadRepository {
             first_byte_time_ms: usage.first_byte_time_ms,
             status: usage.status,
             billing_status: usage.billing_status,
+            request_headers: usage
+                .request_headers
+                .or_else(|| existing.and_then(|existing| existing.request_headers.clone())),
+            request_body: usage
+                .request_body
+                .or_else(|| existing.and_then(|existing| existing.request_body.clone())),
+            provider_request_headers: usage.provider_request_headers.or_else(|| {
+                existing.and_then(|existing| existing.provider_request_headers.clone())
+            }),
+            provider_request_body: usage
+                .provider_request_body
+                .or_else(|| existing.and_then(|existing| existing.provider_request_body.clone())),
+            response_headers: usage
+                .response_headers
+                .or_else(|| existing.and_then(|existing| existing.response_headers.clone())),
+            response_body: usage
+                .response_body
+                .or_else(|| existing.and_then(|existing| existing.response_body.clone())),
+            client_response_headers: usage
+                .client_response_headers
+                .or_else(|| existing.and_then(|existing| existing.client_response_headers.clone())),
+            client_response_body: usage
+                .client_response_body
+                .or_else(|| existing.and_then(|existing| existing.client_response_body.clone())),
+            request_metadata: usage
+                .request_metadata
+                .or_else(|| existing.and_then(|existing| existing.request_metadata.clone())),
             created_at_unix_secs,
             updated_at_unix_secs: usage.updated_at_unix_secs,
             finalized_at_unix_secs: usage.finalized_at_unix_secs,