Add monitoring and health metrics

[leblancfg]

Description

Implement monitoring to track system health and performance.

Acceptance Criteria

• Track scraping success/failure rates
• Measure execution times per provider
• Monitor RSS feed generation time
• Log feed subscriber count (if possible)
• Create status badge for README
• Historical metrics storage

Implementation Notes

• Use GitHub Actions artifacts for metrics
• Generate simple JSON metrics file
• Include in static site dashboard
• Show last 30 days of history
• Add Shields.io badges

Priority: P3 - Low

[leblancfg]

Main focus here is the idea that if a scraping or augmentation job fails, I should get notified – via email is likely the easiest.