wiki: update for v0.8.0 Charts & Visualizations - Add Charts.md comprehensive wiki page (10 chart types, ChartBuilder API, trendlines, error bars, examples) - Update Changelog.md with v0.8.0 section - Update Getting-Started.md CDN URLs to @0.8.0 - Update Home.md with v0.8.0 highlights - Update Sidebar with Charts & Visualizations link - Update Feature-Comparison: charts now :star: (was :x:), 28 categories won - Update API-Reference: add charts property and chart methods to Worksheet Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>