Add telemetry events for degraded mode usage tracking

[pedropaulovc]

Context

Following the implementation of Issue #186, we now log console warnings when the app falls back to GitHub API instead of using iteration artifacts (degraded mode).

Proposed Enhancement

Add telemetry/analytics events (not just console warnings) to track:

• When degraded mode is activated
• The reason for degraded mode (artifact not found, artifact expired, etc.)
• Usage patterns in production

Benefits

• Better understanding of how often users encounter degraded mode
• Data to prioritize improving artifact setup documentation
• Ability to proactively reach out to users experiencing issues

Implementation Notes

• Consider using existing analytics framework if available
• Ensure telemetry respects user privacy settings
• Keep console warnings as-is (useful for debugging)