feat(homepage): apex landing dashboard at home.keithjackson.dev

Deploy Homepage (gethomepage) as the apex landing dashboard aggregating
links to cluster services, in its OWN non-gating post-platform Flux
Kustomization (clusters/base/homepage.yaml, dependsOn platform-config,
wait:false) — mirrors headlamp/oauth2-proxy so a leaf UI can never gate
the platform chain.

- platform/homepage/: plain manifests (ns, config ConfigMap, Deployment,
  Service, default-deny+Cilium ingress NP, apex HTTPRoute). Non-root pod,
  HOMEPAGE_ALLOWED_HOSTS, bundled mdi-* icons (DNS-only egress).
- gateway.yaml: add https-apex + http-apex-redirect listeners for the bare
  apex (the *.home wildcard listener does NOT match it). Apex is already a
  SAN on the wildcard cert — no new Certificate.
- Forward-auth annotated (auth-mode=forward-auth) but NOT enforced: the
  Gateway ext-authz mechanism is an unbuilt Phase-6 WS-NET TODO (same status
  as all other forward-auth apps). Flagged as PM follow-up.

Gate: lint/l0/render-golden(10/10)/l1 green; conformance skipped (no cluster).

Co-Authored-By: Claude Opus 4.8 <[email protected]>

clusters/base/kustomization.yaml

@@ -26,4 +26,8 @@ resources:
   # sit in the gating `platform` tier, where its unhealth stalled platform-config + oauth2-proxy +
   # every apps wave/vm on "dependency not ready" (DECISIONS-LOG: "Headlamp gating stall").
   - headlamp.yaml        # Flux Kustomization -> ./platform/headlamp (dependsOn platform-config)
+  # Homepage apex landing dashboard — POST-platform tier (dependsOn platform-config, wait:false).
+  # A leaf UI at home.keithjackson.dev; same non-gating rationale as headlamp/oauth2-proxy (a UI must
+  # never gate the platform chain). Carries no SOPS secret, so clusters/dev adds no decryption patch.
+  - homepage.yaml        # Flux Kustomization -> ./platform/homepage (dependsOn platform-config)
   - cluster-vars.yaml    # overlay knob surface (base defaults)