feat: add environment::listen

[sapphi-red]

Description

The upside of this approach is that this makes the implementation of environments cleaner IMO.

close #18264

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[sapphi-red]

I tried this API here: https://github.com/sapphi-red/daienjo-architecture/blob/966c60a5a94dcc388ba163ddbe9f2ba3435b2cbb/environment-pkgs/workerd/index.ts#L89-L290

I had to pass in hot always even if it might be false later. I'm making hot noop when it should be hot: false. (previous code)

Other than that, the API worked fine.

[hi-ogawa]

Looks good to me!
In your code, it doesn't override init, so previousInstance is not used? I think I'll also mostly go with listen -> close pattern, but maybe someone finds a good use.

[patak-dev]

Thanks for exploring the different options for the API @sapphi-red!