Feature request: Support `service.beta.kubernetes.io/scw-loadbalancer-healthcheck-port`

[aslafy-z]

Summary

Add support for a new annotation allowing users to explicitly define the LoadBalancer health check port:

service.beta.kubernetes.io/scw-loadbalancer-healthcheck-port: "<port>"

Motivation

The Scaleway CCM currently determines the LoadBalancer health check port based on the per-port nodePort.

However, there is no simple way to force a specific port for the health check without modifying service ports, which is limiting in several use cases (legacy probes, constrained firewall rules, fixed monitoring pipelines).

Proposal

Implement support for:

service.beta.kubernetes.io/scw-loadbalancer-healthcheck-port

Use the same parsing mecanism used on other annotations:

• '18080': a single port, the same port is used for all load balancer backends
• '80:10080,443:10443': port mapping, each backend is configured with his own healthcheck port

Behavior:

1. If this annotation is present, CCM should use the provided integer port value.
2. This port should override the default per-port nodePort
3. Validation should ensure it is a valid TCP/UDP port (1-65535).