REFACTOR(argocd): consolidate App of Apps into single file

- Merge multiple app-of-apps files
- Simplify repository structure

kustomization.yaml

@@ -2,16 +2,14 @@ apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 
 resources:
-  # App of Apps Application
+  # Platform self-reference
   - application.yaml
+
+  # App of Apps (applications, observability, security, storage, web-apps)
+  - app-of-apps.yaml
+
+  # Core infrastructure
   - cert-manager/argocd.yaml
   - traefik/argocd.yaml
-
-  # ArgoCD Image Updater
   - argocd-image-updater/argocd.yaml
-
-  # ArgoCD self-management Application
   - argocd/argocd.yaml
-
-  # Web Apps (App of Apps)
-  - web-apps/argocd.yaml