v0.18.3: Window Dressing

What's Changed

• Add prefab export command by @jlowin in #399
• Rewrite welcome page and README positioning copy by @jlowin in #398
• Extract welcome showcase to examples/hitchhikers-guide/dashboard.py by @jlowin in #400
• Fix vertical carousel gap, add gutter controls position by @jlowin in #401
• Add contributing guidelines, issue templates, version --copy by @jlowin in #403
• Fix Pyodide sandbox on Windows by @jlowin in #405
• Reference CONTRIBUTING.md in CLAUDE.md by @jlowin in #404

Full Changelog: v0.18.2...v0.18.3