Feature: Runtime Execution Simulator

Name Pending.

Testing Lambda code can be difficult / unwieldy. While SAM exists for all supported languages, it is pretty limited in ergonomics, difficult to integrate with in CI, makes testing / infrastructure management unnecessarily complicated, and still requires further orchestration.

In an ideal world, we'd be able to "just" create a runtime with the corresponding service, add all the hooks, tracking, and tracing that we need, execute requests on top, and then verify the results, benchmark, get flamegraphs, etc, all without actually ever deploying, and all from a single `tokio::test`.

I have added a basic server in #1086, so this backlog issue is for extension / reuse of the implementation.

We should start from an internal implementation, and eventually publish a crate so that users can depend on it and integrate it in their CI.

以 issue #1086 中添加的基本服务器作为切入点，然后研究如何扩展或复用它来执行本地 runtime。在实现之前，明确第一个内部里程碑和验收标准，因为该 issue 目前涵盖 hooks、tracing、请求执行、benchmarking 以及最终发布 crate。

由索引模型根据 Issue 内容生成。