feat: Add custom LB health check type using healthCheckNodePort

[aslafy-z]

• Adds a custom health check type that instructs the CCM to:
  • Prefer spec.HealthCheckNodePort when available
  • Use it automatically without requiring explicit annotations
• Ensures safer behavior for externalTrafficPolicy: Local services

References:

• https://kubernetes.io/docs/reference/networking/virtual-ips/#traffic-policies
• https://kubernetes.io/docs/tutorials/services/source-ip/#source-ip-for-services-with-type-loadbalancer
• https://docs.cilium.io/en/stable/network/servicemesh/gateway-api/gateway-api/#externaltrafficpolicy-for-loadbalancer-or-nodeport-services

Closes #192

[aslafy-z]

Replaced by #196