Add monitoring and alerting skill

[PAMulligan]

Description

Create a new skill that generates monitoring endpoints, health checks, and alerting configuration for Nerva APIs.

Why

The current health check is a simple `/health` returning `{ status: "ok" }`. Production APIs need deeper health checks (database connectivity, external service status), Prometheus-compatible metrics endpoints, and alerting configuration.

Acceptance Criteria

• Create `.claude/skills/monitoring-alerting/SKILL.md`
• Generate an enhanced health check endpoint with:
  • Database connectivity check
  • External dependency status
  • Memory usage and uptime
  • Version information
  • Degraded status support (healthy/degraded/unhealthy)
• Generate a `/metrics` endpoint compatible with Prometheus format:
  • Request count by method and status code
  • Request duration histogram
  • Active connections gauge
  • Custom business metrics hooks
• Create alerting rule templates for:
  • High error rate (`> 5%` 5xx responses)
  • High latency (`p95 > 500ms`)
  • Database connection pool exhaustion
• Include Grafana dashboard JSON template
• CI passes

[github-actions]

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[github-actions]

This issue has been automatically closed due to inactivity. If you believe this issue is still relevant, please feel free to reopen it with updated context. Thank you!