chore: harden enterprise production deployment and security automation

[prayingperceptions]

Summary

• add CodeQL analysis and Dependabot npm updates
• add non-root enterprise Docker image and container ignore rules
• add enterprise environment template
• add explicit PostgreSQL migration
• add enterprise production deployment guidance

Security posture

This PR adds operational guardrails around the already-merged durable authorization path. It does not claim independent certification or external penetration testing.

Validation

Repository CI passes on the branch. CodeQL runs on push/PR and weekly schedule.

[github-advanced-security]

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