Bump version, prepare packages

[ouziel-slama]

Note

Medium Risk
Medium risk because it changes the on-the-wire hex encoding for field elements (breaking persisted metadata/roots) and updates golden regression vectors; also adds automated publishing which could mis-publish if misconfigured.

Overview
Prepares the 0.2.0 release and changes field element hex serialization to canonical PrimeField::to_repr() byte order (little-endian). This updates field_to_hex/field_from_hex in kontor-crypto-core, adjusts Poseidon and prepare_file golden/regression expectations, and aligns the WASM/JS surface (worker Merkle path hex encoding and WASM descriptor root checks) to the same byte order.

Adds a GitHub Actions release.yml workflow to publish Rust crates (with a crates.io indexing wait) and then build/publish the npm package, and tweaks CI/WASM/formal workflows to use ubuntu-latest/ubuntu-latest-m runners. Versions are bumped to 0.2.0 across Rust crates and the npm package is renamed to @kontor/kontor-crypto (0.2.0-alpha), with updated crate metadata (license/repo fields) and a new CHANGELOG.md documenting the breaking change.

^{Reviewed by Cursor Bugbot for commit 6d6e9bf. Bugbot is set up for automated code reviews on this repo. Configure here.}

[codspeed-hq]

Merging this PR will not alter performance

✅ 13 untouched benchmarks
⏩ 13 skipped benchmarks¹

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_{Comparing packages (19ad4bf) with main (e7e762e)}

Footnotes

1. 13 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. ↩

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

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^{Reviewed by Cursor Bugbot for commit 5e3dd11. Configure here.}

[codspeed-hq]

Unable to generate the performance report

There was an internal error while processing the run's data. We're working on fixing the issue. Feel free to contact us on Discord or at support@codspeed.io if the issue persists.