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/gateway/README.md

@@ -0,0 +1,34 @@
+# platform/gateway
+
+**Gateway API** (north-south ingress) implemented by **Cilium** + the shared HTTPS Gateway and the
+wildcard TLS certificate.
+
+- **Governing ADRs:** [ADR-0002 — Cilium + Gateway API](../../../home-network-k3s/decisions/adr-0002-cni-cilium.md),
+  [ADR-0006 — cert-manager/Let's Encrypt](../../../home-network-k3s/decisions/adr-0006-tls-cert-manager-letsencrypt.md)
+- **Spec:** [docs/09 — DNS & Ingress](../../../home-network-k3s/docs/09-dns-and-ingress.md)
+- **Serves:** R-DNS-01, R-TLS-01
+- **Owner:** WS-NET (+ WS-SEC for the cert)
+
+## What this stub is
+
+- **`GatewayClass` `cilium`** — Gateway API implemented by Cilium; no separate ingress controller
+  (ADR-0002).
+- **`Gateway` `shared`** — HTTPS listener on `*.home.keithjackson.dev`, TLS terminated with the
+  wildcard cert. App HTTPRoutes attach cross-namespace via a namespace label + ReferenceGrant
+  (rendered by WS-APPS from each ServiceDefinition's `exposure`).
+- **`Certificate` `wildcard-home`** — `*.home.keithjackson.dev` issued by `${ACME_CLUSTER_ISSUER}`
+  (staging in dev, prod in prod — R-ENV-02). Makes onboarding certificate-free (ADR-0006 default).
+
+## Contract (Issuer + Gateway TLS)
+
+The "Issuer + Gateway TLS" interface (`roadmap/workstreams.md`): this Gateway + wildcard cert are what
+every service's HTTPRoute attaches to. ExternalDNS ([`../externaldns`](../externaldns)) publishes the
+`public` records for hostnames routed here. Ingress opens **north-south** only — it does **not** relax
+east-west default-deny (docs/09).
+
+## TODO (later phases)
+
+- **Phase 2 (WS-NET):** pin the L2-announced ingress VIP / IP pool (Cilium L2 announcement, docs/09);
+  add the HTTP→HTTPS redirect route; confirm the cross-namespace ReferenceGrant pattern with WS-APPS.
+- **Public exposure** is a **manual edge port-forward** of 80/443 to the Gateway VIP (single SOHO
+  router, docs/09) — a documented manual step, the analogue of the old pfSense exception.