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.

Start at packages/cloudflare/src/client.ts:55 and review the existing runtime metadata alongside the Bun and Deno behavior mentioned in the issue. Trace which script-name metadata is available through env binding metadata or the wrangler-injected name, and determine whether the compatibility date is reachable at runtime. Done means Cloudflare events report server_name when available and either a usable version or a note explaining why workerd cannot provide one.

索引モデルが issue の本文から書いたものです。