Cutover to V4

[cowboyd]

• switch main branch in repository to v4
• point /effection -> effection.deno.dev rather than effection-www.deno.dev
• adjust workflows to make v4 the latest (v3 publish with latest.v3 tag)
  • ⬇️ Make the v3 dist tag a legacy tag #1056
  • 🎯 publish v4 on "latest" tag #1057
• setup OIDC on JSR
• tag and publish 4.0.0 to JSR and NPM
• publish blog post
• make announcement on discord
• Everyone post on all the social medias
• Submit to JavaScript Weekly
• Post Hacker News