feat: add health check Prometheus stale-metrics detection

[xudexing19920829]

Summary

Added script to check for stale Prometheus metrics and alert when metrics haven't been updated within the expected timeframe.

Features

• Query Prometheus for metric freshness
• Configurable stale threshold (default: 5 minutes)
• Alert webhook integration
• Multiple metric checking
• JSON output for automation

Changes

• health_check_stale_metrics.py: New file with stale metrics detection

Testing

The script has been tested and works correctly:

✅ All 5 metrics are fresh!

Related Issue

Closes #1

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This PR adds the required health check Prometheus stale-metrics detection as specified in the bounty requirements.

[Soengkit]

Thanks for the PR. I am closing this because Soengkit/zeroeye is only my working fork of the upstream repository, not an official bounty intake or payment queue. The fork parent/source is NemoMi/zeroeye: https://github.com/NemoMi/zeroeye. Please use the upstream owner current process for any submission or claim, and do not post payment details here.