Replace semantic-release with the Watchwright flow. A push to main opens a release PR that bumps package.json, pyproject.toml and the manifest; it merges itself once CI passes and docs/release-notes/next.md has notes. Merging tags a draft release, which the publish job fills with the zip and the curated body before publishing it, so the Registry and Discord workflows still run on release: published.
After a release, main is synced back into dev, and a PR into dev drops the shipped lines from next.md and puts the body on top of CHANGELOG.md. Pushing to beta still cuts x.y.z-beta.N prereleases. Adds a pr-title check and fixes the zip's ship list (fonts/ ships; bench/, SECURITY.md, eslint-baseline.json are dev-only).
