feat: add GitOps structure for kubernetes-dashboard, n8n, xslt-lab

- apps/kubernetes-dashboard: raw manifests (namespace, rbac, deployment, service, ingress)
- apps/n8n: Helm values referencing existing n8n-postgresql secret (no password in git)
- apps/xslt-lab: Helm values for xslt-playground chart
- argocd/applications: ArgoCD Application CRDs for all three apps

apps/xslt-lab/values.yaml

@@ -0,0 +1,45 @@
+adsTxt: "google.com, pub-1549720748100858, DIRECT, f08c47fec0942fa0"
+
+frontend:
+  backendUrl: https://backend.xsltplayground.com
+  clarityId: wbgumqnbrz
+  feedbackWebhookUrl: https://n8n.alexandre-vazquez.cloud/webhook/xslt-feedback
+  googleAnalyticsId: G-SHRCV4WZP8
+
+image:
+  backend:
+    repository: ghcr.io/alexandrev/xslt-playground-backend
+    tag: latest
+    pullPolicy: Always
+  frontend:
+    repository: ghcr.io/alexandrev/xslt-playground-frontend
+    tag: latest
+    pullPolicy: Always
+
+replicaCount:
+  backend: 1
+  frontend: 1
+
+hpa:
+  backend:
+    enabled: true
+    minReplicas: 1
+    maxReplicas: 5
+    targetCPUUtilizationPercentage: 80
+  frontend:
+    enabled: true
+    minReplicas: 1
+    maxReplicas: 5
+    targetCPUUtilizationPercentage: 80
+
+ingress:
+  enabled: true
+  className: public
+  annotations:
+    external-dns.alpha.kubernetes.io/target: 192.168.1.10
+    nginx.ingress.kubernetes.io/use-forwarded-headers: "true"
+  hosts:
+  - host: xsltplayground.com
+    paths:
+    - path: /
+      pathType: Prefix