Bonus: Build web dashboard with heatmaps

[copyleftdev]

Description

Create web UI for visualizing analysis results.

Tasks

• Set up React/Next.js frontend
• Build heatmap visualization (DOW × Time)
• Add interactive window drilldown
• Display diagnostics and statistics
• Implement result filtering
• Add export functionality (CSV/JSON)
• Make responsive for mobile

Documentation

• See docs/04-ux-design.md for UX design
• See docs/05-wireframe-flows.md for wireframes

Acceptance Criteria

• Heatmap displays Sharpe ratios correctly
• Interactive tooltips work
• Mobile responsive