support non-result return values in jsg rust

[anonrig]

This PR introduces a cleaner type conversion system for the JSG/Rust bindings by implementing ToJS and FromJS traits. The main improvement is that JSG methods can now return values directly without requiring Result<T, E> wrappers when no error handling is needed.

Additionally, this PR improves the test harness to return and unwrap correct values which simplifies the tests by a significant margin.

[github-actions]

The generated output of @cloudflare/workers-types matches the snapshot in types/generated-snapshot 🎉

[codspeed-hq]

Merging this PR will not alter performance

Summary

✅ 129 untouched benchmarks
⏩ 49 skipped benchmarks¹

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_{Comparing yagiz/support-non-result-return-vals (123ae7e) with main (32d43a0)}

Footnotes

1. 49 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[mikea]

I think error handling design needs a bit more love.

[guybedford]

It would really help to have a clear explanation of the distinction between what types are covered by Type and what types are covered by Wrappable, as it's not clear which set is larger / or if they are disjoint apart from their intersection?

[guybedford]

Also, in the name of ensuring edge cases, it helps to have tests for cases like Result<Option>, Result<Result, ...> as well when dealing with Result interactions.

[anonrig]

Rebased and force pushed.

[anonrig]

Rebased and force pushed.