T-0.1 Flux GitOps layout + dev/prod overlays + platform component skeletons (R-GITOPS-01/03, R-ENV-02, R-PLAT-01)

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

platform/oauth2-proxy/helmrepository.yaml

@@ -0,0 +1,9 @@
+---
+apiVersion: source.toolkit.fluxcd.io/v1
+kind: HelmRepository
+metadata:
+  name: oauth2-proxy
+  namespace: oauth2-proxy
+spec:
+  interval: 1h
+  url: https://oauth2-proxy.github.io/manifests