fix: auto-detect N8N_SECURE_COOKIE from Ingress/TLS settings

Set N8N_SECURE_COOKIE=true only when ingress.enabled=true AND ingress.tls
is configured. All other cases (LoadBalancer, HTTP Ingress) default to false,
eliminating the secure cookie error without manual configuration.

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

Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v2
 name: n8n
 description: A Helm chart for n8n workflow automation on Kubernetes (ARM/Raspberry Pi ready)
 type: application
-version: "2.19.2"
+version: "2.19.2-a"
 appVersion: "2.19.2"
 keywords:
   - n8n