Automate integration validation and migration deploy in CI

[gabedalmolin]

Summary

Automates the final infrastructure-backed quality gate for the auth API.

What changed

• adds a dedicated prisma:migrate:deploy script for deploy-safe migrations
• splits the CI workflow into explicit quality and integration jobs
• runs the real integration suite against PostgreSQL and Redis in GitHub Actions

Validation

• npm run lint
• npm run typecheck
• npm run test:coverage
• GitHub Actions PR checks for quality and integration

Risks/Notes

• local Docker-based integration validation is still blocked on this machine because the Docker daemon is not running
• branch protection still needs to be aligned with the new required check names