ZEN-1954: Network Isolation & Firewall Implementation - Design Complete

Network isolation design complete with 4-tier segmentation:

• Frontend network (nginx only)
• Backend network (API services)
• Data network (databases)
• Monitoring network (prometheus/grafana)

Deliverables:
✅ docker-compose-networks.yml (356 lines, ready for deployment)
✅ Network topology documentation
✅ Traffic flow diagrams
✅ Deployment checklist
✅ Rollback procedure

Files:

• /tmp/docker-compose-networks.yml - Updated compose config
• /tmp/zen1954-network-security.md - Full implementation guide

Status: Ready for Ops team to review and deploy. No code changes required.