stage/prod: bootstrap apps only, prod ksops keys

Bootstrap: cert-manager kargo kargo-infra-pipeline kargo-ci-pipeline kargo-test-env-pipeline kargo-credentials
Other apps arrive via Kargo promotion (dev → test → PR → prod)

infra/traefik-routes/manifests/namespaces.yaml

@@ -1,14 +0,0 @@
-# Ensure namespaces exist for cross-namespace middleware references
-apiVersion: v1
-kind: Namespace
-metadata:
-  name: gitea
-  labels:
-    name: gitea
----
-apiVersion: v1
-kind: Namespace
-metadata:
-  name: kargo
-  labels:
-    name: kargo