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

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

config/samples/providers-config.yaml

@@ -0,0 +1,21 @@
+# Sample --providers-config file (not a Kubernetes manifest). In-cluster
+# this content lives in the providers-config ConfigMap
+# (config/manager/providers_config.yaml); for `make run-dev` a
+# kubernetes-only variant is at hack/providers-dev.yaml.
+#
+# Named provider instances: "gcp-eu" and "gcp-us" are two configs of the
+# same type. spec.provider on a Proxy refers to the name, not the type.
+providers:
+  - name: kubernetes
+    type: kubernetes
+    # kubernetes:
+    #   image: ubuntu/squid:6.6-24.04_edge   # the default
+  - name: gcp-eu
+    type: gcp
+    gcp:
+      project: my-project
+      # network: default            # VPC network name
+      # networkTag: proxy-operator  # firewall tag on created instances
+      # diskSizeGb: 10
+      # auth: Application Default Credentials (workload identity
+      # in-cluster, gcloud ADC locally). No key-file plumbing.