scripts/debug: add kurtosis alerts script and skill

[pinebit]

Summary

• Add scripts/debug/kurtosis_alerts.py — standalone script to fetch Grafana alert history for the "Charon Kurtosis Alerts" folder in a given time range
• Add .claude/skills/kurtosis-alerts/SKILL.md — Claude Code skill that wraps the script, accepts human-friendly time ranges (e.g. "last 30 minutes"), and produces a formatted report grouped by cluster

Sample usage:

❯ /kurtosis-alerts last 10 minutes

⏺ === Kurtosis Alert Report ===
  Time range:  2026-03-27T11:39:13Z to 2026-03-27T11:49:13Z
  Total alerts: 4 transitions (2 unique)
  Clusters:     1

  === Observed Clusters ===
  - kurtosis-lighthouse-lodestar (hash: b043b9d)

  --- kurtosis-lighthouse-lodestar (hash: b043b9d) ---

    11:45:10 UTC  [Normal -> Pending]    Cluster Failed Proposal  (x2)
    11:46:10 UTC  [Pending -> Alerting]  Cluster Failed Proposal  (x2)

  === Alerts Still Firing ===
  - kurtosis-lighthouse-lodestar: Cluster Failed Proposal (since 11:46:10 UTC)

  Summary

  - 1 cluster observed: kurtosis-lighthouse-lodestar
  - The Cluster Failed Proposal alert transitioned from Normal -> Pending -> Alerting within ~1 minute
  - The alert is still firing -- the cluster is currently failing block proposals
  - The "Charon Node is Dead" rule was checked but had no transitions in this window, meaning all nodes are alive
  - Each transition appeared twice (duplicate entries), likely from two matching series in the alert rule

category: feature
ticket: none

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
12.6% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 56.39%. Comparing base (c6c10cd) to head (760d2f6).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4420   +/-   ##
=======================================
  Coverage   56.38%   56.39%           
=======================================
  Files         244      244           
  Lines       32518    32518           
=======================================
+ Hits        18336    18338    +2     
- Misses      11838    11840    +2     
+ Partials     2344     2340    -4     

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