fix(platform): controllers/configs split so CRDs precede their CRs

Un-suspend deadlocked: the single platform Kustomization applies HelmReleases
(which register CRDs) AND custom resources of those CRDs (ClusterIssuer,
Certificate, Kyverno ClusterPolicies) in ONE pass. Flux's server-side apply
fails atomically ('no matches for kind ClusterIssuer') → nothing installs, so
the CRD-registering HelmReleases never run either. Classic ordering deadlock.

Fix (flux2 controllers/configs pattern, applies to dev+prod equally — no
R-ENV-02 divergence): add a platform-config Flux Kustomization (dependsOn
platform, wait) carrying the CRs; platform keeps only the controllers.
- New clusters/base/platform-config.yaml (path ./platform-config, substituteFrom
  cluster-vars, no decryption — no SOPS content); wired into base + apps now
  dependsOn platform-config (transitively waits for platform).
- platform-config/ references the CR files IN PLACE via ../platform/... (Flux
  builds LoadRestrictionsNone; Kyverno policies must stay under platform/kyverno/
  for the CI L0  gate). CR resources dropped from the platform
  component kustomizations (cert-manager, gateway, kyverno).
- Authored the missing Cilium L2 resources (were only a TODO): CiliumLoadBalancerIPPool
  (dev NAT 10.73.0.240-.250) + CiliumL2AnnouncementPolicy (ens*), so Gateway
  LoadBalancer listeners get a VIP. Prod range must be parameterized later.

Verified: platform build has zero CRs; platform-config build has 2 ClusterIssuers,
6 ClusterPolicies, Certificate, Gateway, both Cilium L2 CRs; dev/prod build; gate PASS.

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

platform-config/cilium/l2-announcement-policy.yaml

@@ -0,0 +1,17 @@
+---
+# CiliumL2AnnouncementPolicy — ARP-announce LoadBalancer VIPs on the node LAN so hosts on
+# 10.73.0.0/24 can reach Gateway listeners at the pool IP (l2announcements.enabled=true in the
+# Cilium HelmRelease turns on the controller; this policy scopes WHAT/WHERE it announces).
+# Announces on the primary ethernet interface (cloud-init names it ens3; `^en` matches ens*/enp*).
+apiVersion: cilium.io/v2alpha1
+kind: CiliumL2AnnouncementPolicy
+metadata:
+  name: default-l2
+spec:
+  loadBalancerIPs: true       # announce LoadBalancer Service VIPs (Gateway listeners)
+  externalIPs: false
+  interfaces:
+    - ^en
+  nodeSelector:
+    matchLabels:
+      kubernetes.io/os: linux

platform-config/cilium/l2-ip-pool.yaml

@@ -0,0 +1,16 @@
+---
+# CiliumLoadBalancerIPPool — reserved VIP range for LoadBalancer Services. Gateway API listeners
+# (gatewayClassName: cilium) get their address from here. Range matches the tofu reservation
+# (cilium_l2_vip_range 10.73.0.240-.250) on the k3s-dev NAT 10.73.0.0/24; DHCP is OFF on that
+# network so the range can never be leased elsewhere.
+#
+# NOTE (dev): the range is hardcoded to the dev NAT reservation. A prod overlay must supply the
+# prod LAN range (parameterize via cluster-vars when prod hardware is built). See DECISIONS-LOG.
+apiVersion: cilium.io/v2alpha1
+kind: CiliumLoadBalancerIPPool
+metadata:
+  name: default-pool
+spec:
+  blocks:
+    - start: "10.73.0.240"
+      stop: "10.73.0.250"