feat(headers): sync SuperHeaders with native Headers

[alexandredev3]

This PR synchronizes SuperHeaders with the parent Headers class to ensure compatibility with Bun.

Previously, SuperHeaders stored data only in its internal #map without updating the parent Headers state. As a result, when running on Bun, the Response constructor would receive empty headers.

This appears to be because Bun accesses the parent Headers class's internal storage directly, bypassing overridden methods. Other runtimes, such as Node.js, seem to rely on JavaScript-level methods like entries(), which is why they behaved correctly.

The most reliable solution found was to explicitly call methods like super.append, super.set, and super.delete alongside the internal updates to make Headers state visible to Bun.

resolves #10872

[markdalgleish]

Thanks for raising this issue. I further explored what a complete solution would look like here: #10904. This most notably adds support for detecting mutations to header property accessors, e.g. headers.allow = ['GET', 'POST', 'PUT'].

As a result, we've opted instead to simplify the model, avoiding subclassing Headers and other native classes in order to avoid this category of issue entirely: #10911