v1.0.9 Infrastructure security audit

[sudoshi]

Roadmap execution issue derived from ROADMAP.md.

Release: v1.0.9
Category: Security
Area: Infrastructure
Priority: P1
Risk: High
Work Type: Audit
Target Date: 2026-05-04

Validate infrastructure-level protections across the deployed stack.

Scope:

• Verify all Docker containers run as non-root.
• Audit secret file permissions.
• Enforce authentication for Redis, Orthanc, and Grafana.
• Scan Docker images for known CVEs.
• Review network segmentation between containers.

Done Criteria

• Implementation, audit, or validation work is completed for this scope.
• Evidence is captured with code, tests, or review notes as appropriate.
• Documentation is updated when the work changes user or developer behavior.