feat(security): add Pod Security Standards (PSA) namespace configurations

- Add namespace templates for privileged, baseline, and restricted levels
- Include compliant deployment examples for baseline and restricted
- Add migration audit script for checking namespace compliance
- Document PSA levels, enforcement modes, and migration strategy

Follows Kubernetes Pod Security Admission best practices for 2025+.
Reference: https://kubernetes.io/docs/concepts/security/pod-security-standards/

README.md

@@ -15,12 +15,14 @@ Production-ready Kubernetes manifests with security best practices, resource lim
 ├── secrets/           # Secret management patterns
 ├── networkpolicies/   # Network isolation
 ├── rbac/              # Role-based access control
-└── monitoring/        # Prometheus, alerts, ServiceMonitors
+├── monitoring/        # Prometheus, alerts, ServiceMonitors
+└── pod-security/      # Pod Security Standards (PSA) configuration
 ```
 
 ## Features
 
 - ✅ Security contexts and pod security standards
+- ✅ **Pod Security Admission (PSA)** namespace configurations
 - ✅ Resource requests/limits
 - ✅ Liveness/readiness probes
 - ✅ Network policies for isolation