add neuron-web phase-1 deploy on Legion

Stand up the elb-built native El landing server on Legion k3s alongside
the existing Cloud Run prod marketing site. Image is built on
gitea-runner-1 from elb-emitted .c files + native cc and pushed to
registry.neuralplatform.ai/neuron-web:dev-dfe41234. Deployment exposes
web-stage.neuralplatform.ai via Traefik + Cloudflare tunnel.

The point is to have a working local instance we can iterate against
while we redesign the CI/CD pipeline; nothing here replaces the Cloud
Run deploy yet.

* k8s/neuron-technologies/web/ — namespace, deployment, service, ingress,
  registry-pull-secret + externalsecret pulling anthropic/supabase keys
  from Vault
* apps/neuron-web.yaml — Argo CD Application
* dns-neuralplatform.tf, main.tf — CNAME + tunnel ingress for
  web-stage.neuralplatform.ai

servers/legion/main.tf

@@ -265,6 +265,17 @@ resource "cloudflare_zero_trust_tunnel_cloudflared_config" "legion" {
       service  = "http://headscale.headscale.svc.cluster.local:8080"
     }
 
+    # web-stage.neuralplatform.ai — Phase 1 Legion deploy of neuron-web
+    # (native El landing server). Routes via Traefik to the neuron-web
+    # service in the neuron-web namespace.
+    ingress_rule {
+      hostname = "web-stage.neuralplatform.ai"
+      service  = "https://traefik.kube-system.svc:443"
+      origin_request {
+        no_tls_verify = true
+      }
+    }
+
     # Catch-all — must be last
     ingress_rule {
       service = "http_status:404"