Migrate to new MalloyRenderer API and improve visualization docs

[mtoy-googly-moogly]

Summary

• Migrate from <malloy-render> web component to new MalloyRenderer JS API — the old web component is no longer exported by @malloydata/render. Now uses createViz() / setResult() / render() pattern with API.util.wrapResult() for serialization.
• Fix CSS bleed from Shadow DOM removal — scope div.header rule to div.top > div.header, add table reset block inside .result-inner to prevent site styles from bleeding into renderer output.
• Upgrade @malloydata/malloy and @malloydata/render to 0.0.358, remove unused jsdom / @types/jsdom dependencies.
• Clean up renderer docs — delete renderer.malloynb, legacy_renderer.malloynb, renderer_next.malloynb; consolidate TOC under single "Visualizations" section.
• Add tag parameter reference to each visualization page (bar charts, line charts, scatter charts, dashboards, lists, numbers, links, pivots, transpose, shape maps, segment maps).
• Add quick reference cheatsheet to the visualizations overview page with links to individual pages.
• Fix typos across multiple doc pages.

Test plan

• npm run build completes without errors
• Verify charts render correctly on key pages (numbers, bar charts, line charts, scatter charts)
• Verify tables have correct font size (12px, not 22px)
• Verify pivot tables, dashboards, and maps render correctly
• Verify links in overview cheatsheet point to correct pages
• Verify deleted renderer docs pages return 404 / are not linked

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