Allow annotations on Traefik ingress routes

[jkossis]

Summary

• Add traefik.annotations to the cluster chart values
• Apply those annotations to generated HTTPS and TCP IngressRouteTCP resources
• Document the new values key in the cluster chart README

Use case

When external-dns is configured with the Traefik source, operators often need annotations on the Traefik route objects themselves. For example, Pi-hole or other DNS providers can use:

traefik:
  annotations:
    external-dns.alpha.kubernetes.io/target: traefik

This lets external-dns discover the generated RavenDB HTTPS and TCP IngressRouteTCP resources and create DNS records for both publicServerUrl and publicServerUrlTcp hostnames without requiring users to patch Helm-managed resources after install.

Validation

• helm lint helm/cluster-chart
• helm template ravendb-cluster helm/cluster-chart -n test with traefik.annotations.external-dns.alpha.kubernetes.io/target=traefik

[jkossis]

@TheGoldenPlatypus tagging for visibility

[jkossis]

@poissoncorp tagging for visibility