Cloudflare events have no runtime version and no server name

`packages/cloudflare/src/client.ts:55`:

```ts
// TODO: Grab version information
runtime: { name: 'cloudflare' },
// TODO: Add server name
```

Bun reports `{name:'bun', version:'1.3.14'}` and Deno reports the Deno version. Cloudflare reports neither a version nor a `server_name`, so events cannot be grouped or filtered by worker.

**Work item.** Set `server_name` from the script name where it is available (`env` binding metadata or the wrangler-injected name). For the version, either use the compatibility date if reachable at runtime or delete the TODO with a note saying workerd exposes nothing usable.

从 packages/cloudflare/src/client.ts:55 开始，结合 issue 中提到的 Bun 和 Deno 行为，检查现有的运行时元数据。追踪通过 env binding metadata 或 wrangler 注入的名称可以获得哪些脚本名称元数据，并确定运行时是否可以获取 compatibility date。完成标准是：Cloudflare 事件在可用时报告 server_name，并提供一个可用的版本，或附带说明 workerd 无法提供版本的原因。

由索引模型根据 Issue 内容生成。