feat(matrix-synapse): 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.

matrix-synapse/Chart.yaml

@@ -3,7 +3,7 @@ name: matrix-synapse
 description: A Helm chart to deploy a Matrix Synapse server on Kubernetes
 icon: https://raw.githubusercontent.com/element-hq/synapse/develop/docs/favicon.png
 type: application
-version: 8.0.0+upv1.159.0
+version: 8.1.0+upv1.159.0
 appVersion: "v1.159.0"
 maintainers:
   - name: jklein