feat: deploy to Frostmoln production (#391)

Moves the production deploy from AWS to the Frostmoln production cluster (namespace `schemas`), with unboundsoftware/schemas.

- `deploy-prod` (AWS, failing since CI left AWS) → `deploy-prod-frostmoln`: `deploy prod-frostmoln -n schemas`.
- Restricted Pod Security: `nginxinc/nginx-unprivileged` (uid 101, port 8080; 1.31.7 isn't published for it yet, so 1.31.6). `nginx.conf`: no `user`, pid and temp paths under `/tmp`, `listen 8080`. Configs copied with `--chmod=644`. Service is ClusterIP.
- `autoscale-prod`/`pdb-prod` → `-prod-frostmoln`; the ALB ingress → a Traefik one for `/` on `schemas.unbound.se` (the API's `/query` ingress wins on the longer path).

Checked locally (amd64): as uid 101 with all capabilities dropped, `/health`, `/` and SPA routes 200, security headers present.

**Merge with** the schemas PR, after infra#1878 is applied.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

https://claude.ai/code/session_01Ma8eHhW59hLAJuLzBnLvUu
Reviewed-on: #391

k8s/ingress-prod-frostmoln.yaml

@@ -0,0 +1,21 @@
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: schemas-app
+  annotations:
+    traefik.ingress.kubernetes.io/router.entrypoints: websecure
+    traefik.ingress.kubernetes.io/router.tls.certresolver: letsencrypt
+spec:
+  ingressClassName: traefik
+  rules:
+    - host: "schemas.unbound.se"
+      http:
+        paths:
+          # Everything but /query, which the schemas API's longer path takes.
+          - path: /
+            pathType: Prefix
+            backend:
+              service:
+                name: schemas-app
+                port:
+                  number: 80