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>

Chart.yaml

@@ -0,0 +1,22 @@
+apiVersion: v2
+name: n8n
+description: A Helm chart for n8n workflow automation on Kubernetes (ARM/Raspberry Pi ready)
+type: application
+version: "2.19.2"
+appVersion: "2.19.2"
+keywords:
+  - n8n
+  - workflow
+  - automation
+  - integration
+maintainers:
+  - name: Pieter
+    url: https://git.cafepieters.com/helmchart/repo/
+home: https://n8n.io/
+sources:
+  - https://github.com/n8n-io/n8n
+icon: https://n8n.io/favicon.ico
+kubeVersion: ">=1.19.0-0"
+annotations:
+  category: Automation
+  licenses: Sustainable Use License