Add Helm chart scaffold with Chart.yaml, values.yaml, helpers, and all templates

Adds full Helm chart for GroomBook including migration job (pre-install/pre-upgrade hook), CNPG cluster (operator mode), DragonflyDB (integrated + operator modes), API/web deployments, services, and ingress templates.

Resolves GRO-89.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

charts/groombook/templates/api-service.yaml

@@ -0,0 +1,17 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ include "groombook.fullname" . }}-api
+  labels:
+    {{- include "groombook.labels" . | nindent 4 }}
+    app.kubernetes.io/component: api
+spec:
+  type: {{ .Values.api.service.type }}
+  selector:
+    {{- include "groombook.selectorLabels" . | nindent 4 }}
+    app.kubernetes.io/component: api
+  ports:
+    - port: {{ .Values.api.service.port }}
+      targetPort: 3000
+      protocol: TCP
+      name: http