Debug: Warn on unsupported properties with Proxy

For debug mode only, it might be nice to add a JS proxy that warns when setting unsupported properties. E.g. with a short-link to new issue template for `worker-dom`.

Thinking about the easiest way to integrate this. If we go with the separate debugging module fetched at runtime, we'd need one for the worker and one for the main-thread. Maybe another output variant is justified? 🤔

Start by reviewing the worker-dom debug-mode integration and how runtime modules or output variants are currently produced. Compare the separate debugging-module options for the worker and main thread, and define the supported-property warning behavior and issue-template link. Done requires an agreed integration approach and debug-only behavior.

Written by the indexing model from the issue text.