feat: integrate OpenTelemetry tracing into collector

[d0ugal]

Integrate OpenTelemetry Tracing into Collector

This PR adds full OpenTelemetry tracing integration to the ghcr-exporter collector.

🚀 Changes

• GHCRCollector: Added tracing spans for each package collection cycle

  • Span attributes include: package name, owner, repo, interval
  • Duration tracking in spans
  • Error recording for failed collections
  • Collection completion events

• Main.go: Updated to pass app instance to collector for tracing access

• Tests: Updated all tests to include app parameter

📊 Tracing Features

Each collection cycle now creates a span with:

• Package metadata (name, owner, repo, interval)
• Collection duration
• Success/failure status
• Error details (when applicable)

🧪 Testing

• ✅ Builds Successfully: All dependencies resolved
• ✅ Tests Pass: All unit and integration tests updated and passing
• ✅ Tracing Integration: Spans created for collection operations
• ✅ Ready for Testing: Test with docker-compose.dev.yaml

📝 Usage

Tracing is automatically enabled when configured via environment variables:

environment:
  - TRACING_ENABLED=true
  - TRACING_SERVICE_NAME=ghcr-exporter
  - TRACING_ENDPOINT=http://your-otel-collector:4318/v1/traces

Ready for review and merge! 🎯