refactor: change extra_data to extra_fields

[Its-Just-Nans]

Part 1 of the extra field rewrite

[amazon-q-developer]

This PR successfully refactors the extra field handling system by introducing a CustomExtraField type to replace the previous raw Vec<u8> approach. The changes improve type safety and code organization while maintaining backward compatibility. All modifications follow consistent patterns across the codebase, and the test suite has been appropriately updated to reflect the new API. No blocking issues identified.

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[gemini-code-assist]

Code Review

This pull request refactors ZIP extra field management by replacing raw byte buffers in ExtendedFileOptions with a structured CustomExtraField type, updating the writer and associated tests accordingly. Feedback highlights a bug in CustomExtraField::new_from_raw where the payload incorrectly includes size bytes, and identifies a redundant bounds check. Furthermore, an optimization was suggested to minimize memory allocations when collecting serialized extra fields.

[Pr0methean]

This is a partial review (covers all except src/write.rs).

[Its-Just-Nans]

@Pr0methean

Thanks for the review. Note that this MR is only the PART 1 of the extra field review.
I'm splitting the MR in multiple MRs for an easier review. But note that some code on this MR will change with the next one

done

[Its-Just-Nans]

CI is showing a bug in the latest nightly

cargo +nightly miri test --target aarch64_be-unknown-linux-gnu --all --no-default-features zip64_with_leading_junk

EDIT: see #843