fix: improve npm release process (#2055)

This improves the release process by introducing
`scripts/publish_to_npm.py` to automate publishing to npm (modulo the
human 2fac step).

As part of this, it updates `.github/workflows/rust-release.yml` to
create the artifact for npm using `npm pack`.

And finally, while it is long overdue, this memorializes the release
process in `docs/release_management.md`.

.github/workflows/rust-release.yml

@@ -182,7 +182,11 @@ jobs:
             --release-version "${{ steps.release_name.outputs.name }}" \
             --tmp "${TMP_DIR}"
           mkdir -p dist/npm
-          (cd "$TMP_DIR" && zip -r "${GITHUB_WORKSPACE}/dist/npm/codex-npm-${{ steps.release_name.outputs.name }}.zip" .)
+          # Produce an npm-ready tarball using `npm pack` and store it in dist/npm.
+          # We then rename it to a stable name used by our publishing script.
+          (cd "$TMP_DIR" && npm pack --pack-destination "${GITHUB_WORKSPACE}/dist/npm")
+          mv "${GITHUB_WORKSPACE}"/dist/npm/*.tgz \
+             "${GITHUB_WORKSPACE}/dist/npm/codex-npm-${{ steps.release_name.outputs.name }}.tgz"
 
       - name: Create GitHub Release
         uses: softprops/action-gh-release@v2