feat: Add opt-in starter packs to help users adopt and customize declarative security policies - #112

Summary

Add opt-in starter packs to help users adopt and customize declarative security policies.

• Provide PCI-inspired, HIPAA-inspired, and internal-service packs with two focused rules each.
• Demonstrate numeric, regex, Boolean, and connectivity predicates.
• Include a synthetic model, tested CLI examples, control references, scope limitations, and remediation guidance.

These examples evaluate recorded model evidence; they do not certify compliance. No runtime or dependency changes.