fix argocd install + add root bootstrap Application manifest

- remove server.httproute from argocd values.yaml: helm install failed
  since Gateway API CRDs (installed by envoy-gateway, wave 2) don't
  exist yet; HTTPRoute is already applied manually in Phase 6
- add bootstrap-app.yaml as the Git-committed root/seed Application,
  replacing ad-hoc UI creation (GitOps anti-pattern: apps not stored
  in Git can't be recreated)

manifests/argocd/values.yaml

@@ -24,9 +24,3 @@ configs:
 
 server:
   replicas: 1
-  httproute:
-    enabled: true
-    parentRefs:
-      - name: envoy-gateway
-        namespace: gateway-system
-        sectionName: http