📊 Add analytics and monitoring

[chitcommit]

Analytics & Monitoring

Add analytics to track Billy's usage and performance.

Metrics to Track:

1. Usage Metrics

   • API call volume by endpoint
   • Language distribution
   • BS score distribution
   • Most common code smells detected

2. Performance Metrics

   • Response times
   • AI model performance
   • Error rates
   • Fallback usage

3. Quality Metrics

   • User feedback (thumbs up/down)
   • Code improvement tracking

Implementation:

• Cloudflare Analytics
• Custom metrics dashboard
• Export to external analytics (optional)

Acceptance Criteria:

• Basic analytics implemented
• Dashboard created
• Performance monitoring active

Priority: Low