CHORE(deploy): use argocd for kaniko

Infrastructure as Code:
- Add Kaniko namespace and RBAC manifests
- Create ArgoCD Application for Kaniko infrastructure
- Kustomize configuration for Kaniko resources

Workflow improvements:
- Remove kubeconfig dependency
- Use in-cluster ServiceAccount (runner runs in K8s)
- Remove all sudo commands
- Simplify Kubernetes access

GitOps workflow:
1. Push manifests to Git
2. ArgoCD auto-syncs infrastructure
3. Gitea runner uses ServiceAccount permissions
4. Kaniko builds run in kaniko-builds namespace

Benefits:
- True GitOps approach
- No secrets management needed
- Declarative infrastructure
- ArgoCD handles reconciliation
- Audit trail in Git

deploy/kaniko/kustomization.yaml

@@ -0,0 +1,6 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - namespace.yaml
+  - rbac.yaml