feat: add Helm chart and release workflow

Adds a Helm chart under charts/hightower/ as an alternative to the
Flux/Kustomize deployment. Distributed via GitHub Pages (gh-pages branch).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

charts/hightower/templates/api-role.yaml

@@ -0,0 +1,16 @@
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: {{ include "hightower.api.fullname" . }}
+  labels:
+    {{- include "hightower.labels" . | nindent 4 }}
+rules:
+  - apiGroups: ["batch"]
+    resources: ["jobs"]
+    verbs: ["create", "get", "list", "delete", "watch"]
+  - apiGroups: [""]
+    resources: ["pods"]
+    verbs: ["get", "list", "watch"]
+  - apiGroups: [""]
+    resources: ["pods/log"]
+    verbs: ["get"]