Interactive HTML dashboard for benchmark reports

[rudrakshkarpe]

Summary

Formalize the reference generate_behavior_report.py into a first-class --format html option with filtering, drill-down, and trend charts.

Scope

• dual-llm-bench report --format html command
• Filterable metrics table
• Per-sample drill-down with trace details
• Trend charts across multiple runs (if history available)
• Self-contained single HTML file (inline CSS/JS)

Acceptance Criteria

• HTML report renders correctly in modern browsers
• Includes all metrics with visual gauges
• Per-sample detail view
• No external dependencies (fully self-contained HTML)