Prepare 0.7.0-rc.1 release candidate

[zuchka]

Summary

• bump package.json from 0.7.0-rc.0 to 0.7.0-rc.1
• keep the root package-lock metadata synchronized
• prepare the browser-native ESM fix from Fix native browser ESM loading #122 for prerelease publication

Validation

• npm ci
• version consistency check across package.json and package-lock.json
• complete prepublishOnly gate
• CommonJS, ESM, packed-package, and TypeScript tests
• Are the Types Wrong validation
• npm publish --dry-run --tag next --access public
• zero production audit findings

The dry-run tarball contains the expected eight files and identifies itself as remove-markdown@0.7.0-rc.1.

After merge

Publish a GitHub prerelease tagged 0.7.0-rc.1 from the merged commit. The release event will trigger .github/workflows/publish.yml, which will publish the package under npm's next dist-tag. This PR itself does not publish anything.