Include Preact signal

Hey there,

thank you for providing `htm` and thus a simple build tools free solution to use Preact!

Recently a new extension to Preact has been published, namely [@preact/signals](https://github.com/preactjs/signals). As this is an amazing improvement to the way to use Preact I am wondering if there are any plans to include it into the whole `htm` standalone package?

This would be amazing.

Thanks you very much!

Sincerely,
Happy Striker

Review the standalone htm package and the linked @preact/signals project first. The request does not identify files, an API, compatibility requirements, or tests, so define the integration scope and acceptance criteria with maintainers before attempting implementation.

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