Wire the composition root: flags, providers, runnables, manifests, samples, docs

Co-Authored-By: Claude <noreply@anthropic.com>

config/samples/kustomization.yaml

@@ -1,4 +1,8 @@
 ## Append samples of your project ##
+# providers-config.yaml is deliberately absent: it is a sample
+# --providers-config file, not a Kubernetes manifest.
 resources:
-- crawl_v1alpha1_proxy.yaml
+- proxy_kubernetes.yaml
+- proxy_gcp.yaml
+- proxy_external.yaml
 # +kubebuilder:scaffold:manifestskustomizesamples