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

Dockerfile

@@ -12,9 +12,10 @@ RUN npm run postinstall && npm run generate && npm run lint && npm run test:cove
 FROM scratch as export
 COPY --from=builder /build/coverage /
 
-FROM amd64/nginx:1.31.7@sha256:227f31dac037a2f1cdbd17ca9eec940a76c6c1b3187f5285eca2c3edb5d19c31
+# Unprivileged (uid 101, port 8080): Frostmoln enforces restricted Pod Security.
+FROM nginxinc/nginx-unprivileged:1.31.6@sha256:1d26a516fb93b18f9c0214dc9c645054486e516f13ff09ef63d5bd5c622278a2
 MAINTAINER Joakim Olsson <joakim@unbound.se>
 
-COPY ./nginx/nginx.conf /etc/nginx/nginx.conf
-COPY ./nginx/security_headers.conf /etc/nginx/security_headers.conf
+COPY --chmod=644 ./nginx/nginx.conf /etc/nginx/nginx.conf
+COPY --chmod=644 ./nginx/security_headers.conf /etc/nginx/security_headers.conf
 COPY --from=builder /build/.output/public/ /usr/share/nginx/html/