Conventions batch 2: flexible ingress standard, configurable probes

Establish the flexible ingress standard from #32 in template-chart and
document it in README/CLAUDE.md: ingress.domain and ingress.clusterIssuer
stay required, new ingress.className value (default nginx) replaces the
hardcoded ingressClassName, new optional ingress.annotations are merged
with the cert-manager cluster-issuer annotation, TLS secret name
unchanged (tls-<release>-<chart>-ingress).

Apply the standard to cyberchef and patchmon (the two charts without an
own batch-3 major PR) and make the patchmon probes values-configurable
(server + guacd, rendered through tpl so the default Host header keeps
following ingress.domain). Defaults render semantically identical to the
previous hardcoded output.

cyberchef 5.0.1 -> 5.1.0, patchmon 5.0.1 -> 5.1.0 (minor, additive).

cyberchef/Chart.yaml

@@ -5,7 +5,7 @@ icon: https://raw.githubusercontent.com/gchq/CyberChef/master/src/web/static/ima
 
 type: application
 
-version: 5.0.1+up11.4.0
+version: 5.1.0+up11.4.0
 appVersion: "11.4.0"
 
 maintainers: