Move the haproxy edge behind the external Traefik (#492)

The haproxy edge holds its own DMZ VIP, a second public entry point alongside
traefik-external that must be firewalled and DNS'd separately. Traefik can
front it with TLS passthrough, leaving haproxy's certs and backends untouched.

- Add a `traefik-external` Gateway: HTTP :80 plus Passthrough TLS :443.
- TLSRoute the 12 `fe_https.map` hostnames to haproxy:443; HTTPRoute 301s :80.
- Make the Service ClusterIP on 443 only, releasing 198.18.199.1.
- Drop `fe_http`, `be_letsencrypt` and `fe_http.map`; certs are DNS-01 only.

Client IP now reads as a Traefik pod — the Gateway provider cannot emit PROXY protocol to a TLSRoute backend. `sessionAffinity` goes too (it would pin Traefik pods, not clients); SRVNAME cookies keep persistence.

Reviewed-on: #492
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

apps/base/haproxy/gateway.yaml

@@ -0,0 +1,31 @@
+---
+# External (DMZ) front for the haproxy edge on the traefik-external LB VIP
+# 198.18.199.0. The :443 listener is TLS Passthrough: haproxy owns the three
+# wildcard certs and terminates behind Traefik, so there are no certificateRefs
+# here. Listener hostnames are deliberately unset and the routes carry the
+# explicit hostname list instead; allowedRoutes Same keeps other namespaces off
+# these listeners.
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  name: haproxy
+  namespace: haproxy
+  labels:
+    traefik.io/instance: external
+spec:
+  gatewayClassName: traefik-external
+  listeners:
+    - name: http
+      port: 80
+      protocol: HTTP
+      allowedRoutes:
+        namespaces:
+          from: Same
+    - name: https-passthrough
+      port: 443
+      protocol: TLS
+      tls:
+        mode: Passthrough
+      allowedRoutes:
+        namespaces:
+          from: Same