Epic: Cross-cutting — Platform hardening #83

Objective

Platform hardening: observability, data policy, deployment, and release gate.

Scope

Domain events (as phases demand), observability beyond logs (metrics, tracing), data retention/GDPR policy, deployment step in CI when target is chosen.

Acceptance criteria

• Metrics and tracing operational
• GDPR/data retention policy implemented
• Deployment pipeline ready
• 1.0.0 release gate criteria met

References

• docs/roadmap/README.md