feat(stalwart): networkPolicy.ingress.ambientMesh

Gitea #143. Additive, default false, so the render is byte-identical to the
previous release - proven by diffing both renders against origin/main rather
than asserted.

Switched on it adds 15008/TCP, ztunnel's HBONE tunnel, to the rule carrying
the probe port, and - inside that rule's source-restricted branch -
169.254.7.127/32, the address the kubelet's probes arrive from once the pod is
in the mesh. Ambient does not bypass NetworkPolicy enforcement, so without the
port a pod whose namespace has joined the mesh is unreachable.

The two halves are one value because the second is the one nobody thinks of:
15008 added by hand leaves a policy that passes review and drops every probe
the first time probeSources is narrowed, and a pod that never becomes Ready
reads as a broken application rather than as a policy.

Minor, not major: additive value, unchanged default, unchanged render.

stalwart/Chart.yaml

@@ -37,7 +37,7 @@ type: application
 #
 # Note for whoever bumps this next: the suffix tracks appVersion, so a major
 # here keeps the +up<appVersion> it was merged with.
-version: 3.0.0+upv0.16.26
+version: 3.1.0+upv0.16.26
 appVersion: "v0.16.26"
 
 maintainers: