[kasparsd]

Fixes #527.

• Standardize the plugin release artifact build from a sequence of git archive and rsync scripts across multiple places into a single bin/release.js which builds the plugin ZIP with the correct root-level directory and honors the existing .distignore list.

• Use the improved release workflow to attach plugin ZIPs to Playground previews and now also tagged releases.

While doing the above, we:

• introduce standardized JS tools under bin/... to be used instead of arbitrary utilities like zip and rsync which might not be available at predictable versions.
• introduce linting for JS via wp-scripts shared tooling.
• mark releases as pre-releases on GitHub if the tag contains a dash (per semver).
• bump Node to 22 in .nvmrc and GitHub actions that hardcode the version.