Implement deployer-owned delivery role

[fujiwaranosai850]

Summary

• add the first-class deployer role to the registry, docs, and prompt loading tests
• move promotion and acceptance workflow ownership to deployer in defaults and config validation
• update delivery dispatch/completion tests and helpers for deployer-owned delivery states

Testing

• npx tsx --test lib/config/schema.test.ts lib/roles/registry.test.ts lib/dispatch/bootstrap-hook.test.ts lib/services/delivery-phases.test.ts lib/services/pipeline-delivery.test.ts