Generate comprehensive HTML QC reports with interactive plots

## Summary Create PEPPRO-style interactive HTML reports with comprehensive QC visualizations and metrics. ## Features to implement - Interactive HTML report generation - Cumulative fraction of reads in features (cFRiF) plots - TSS enrichment profile plots - Pause index distribution histograms - Insert size distribution visualizations ## Implementation details - Create HTML template with JavaScript interactivity - Generate plot data in JSON format - Integrate with existing MultiQC workflow - Add project-level summary reports ## Acceptance criteria - [ ] Interactive HTML reports generated - [ ] All QC plots functional and interactive - [ ] Integration with MultiQC - [ ] Project-level summaries - [ ] Mobile-responsive design ## References - PEPPRO HTML reporting system