docs: payout reconciliation runbook per drift class

[Calebstack]

Overview

This PR publishes a payout reconciliation runbook that maps every PayoutDriftClass to a triage owner, ETA target, and rollback lever, and cross-links it from PagerDuty alert descriptions produced by payoutDriftDetector.

Related Issue

Closes #666

Changes

📘 Runbook + alert wiring

• [MODIFY] docs/runbooks/payout-reconciliation.md
  • PayoutDriftClass playbook matrix, SEV-1 in 15 minutes table with named rotations, Grafana screenshots-of-truth PromQL.
• [MODIFY] src/services/payoutDriftDetector.ts (+ tests)
  • Embeds runbook_url and pagerduty_description with per-class counts when payout_drift_alarm fires.
• [MODIFY] src/db/repositories/payoutDriftRepository.ts
  • Exports canonical PayoutDriftClass type.

Verification Results

npx jest --runInBand --forceExit src/services/payoutDriftDetector.test.ts --coverage=false
✅ passed

npm run validate:alert-mappings
✅ payout_drift_* alerts mapped

Acceptance Criteria	Status
Drift class → owner / ETA / rollback matrix	✅ Runbook playbook table
SEV-1 in 15 minutes with named rotations	✅ Named PD schedules documented
Grafana sample queries / screenshots-of-truth	✅ Panel PromQL checklist
Cross-link from detector alert descriptions	✅ runbook_url + PD description

Timeline

• Calebstack committed