Wave 1 Onboarding for High-Activity Repositories

## Goal
Onboard the first wave of highest-activity/critical repositories with low disruption.

## Why
Developers need a concrete onboarding checklist and cutover criteria, not only rollout intent.

## Candidate Repositories
- communication
- persistency
- reference_integration
- baselibs
- lifecycle
- tooling
- feo
- cicd-workflows
- cicd-actions

## Required Readiness Checklist (per repo)
- Lane A command set documented and runnable in CI.
- Required artifacts emitted and schema-valid.
- Policy checks wired and producing machine-readable decisions.
- Branch protection check names mapped.
- Waiver owner and rollback owner identified.

## Rollout Steps
1. Enable soft-fail mode for one sprint.
2. Track failures by category (missing artifacts, policy fail, test fail, infra fail).
3. Fix top failure classes and rerun.
4. Switch to hard-fail for agreed policy rules.

## Docs-as-code pilot criteria
- Existing traceability metrics and gate scripts run in Lane A.
- Evidence artifacts uploaded from CI and consumed by policy checks.
- Soft-fail to hard-fail transition completed with documented outcomes.

## Done When
- Every Wave 1 repo passes readiness checklist.
- All Wave 1 repos emit required evidence artifacts.
- Hard-fail mode enabled for agreed policy rules.
- Rollout report records key failures, fixes, and cutover date per repo.

Parent: https://github.com/eclipse-score/score/issues/2827