feat: add n8n Helm chart for Kubernetes on Raspberry Pi (ARM64)

- n8nio/n8n 2.19.2 (multi-arch, linux/arm64 ready)
- Single-container deployment with persistent storage
- SQLite default / PostgreSQL option
- Basic auth, encryption key via Secret
- Ingress, HPA, PDB, NetworkPolicy support
- Gitea CI: weekly auto-update + release workflow

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

templates/networkPolicy.yaml

@@ -0,0 +1,22 @@
+{{- if .Values.networkPolicy.enabled }}
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: {{ include "n8n.fullname" . }}
+  labels:
+    {{- include "n8n.labels" . | nindent 4 }}
+spec:
+  podSelector:
+    matchLabels:
+      {{- include "n8n.selectorLabels" . | nindent 6 }}
+  policyTypes:
+    {{- toYaml .Values.networkPolicy.policyTypes | nindent 4 }}
+  {{- if .Values.networkPolicy.ingress }}
+  ingress:
+    {{- toYaml .Values.networkPolicy.ingress | nindent 4 }}
+  {{- end }}
+  {{- if .Values.networkPolicy.egress }}
+  egress:
+    {{- toYaml .Values.networkPolicy.egress | nindent 4 }}
+  {{- end }}
+{{- end }}