docs(portal-openbaar): record openbaar decisions + walking-skeleton public-visibility demo (refs #10)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/demo-script.md

@@ -168,3 +168,32 @@ curl -fsS http://localhost:8120/register | jq 'length'  # → unchanged
 
 > `bsn` / `naam_placeholder` are deferred (ADR-0008) — the notification doesn't carry them and
 > the subscriber may not read OpenZaak directly (§8.1). They surface in a later slice.
+
+---
+
+## S-09 — Openbaar Register portal (public visibility)
+
+**Outcome:** the entry a zorgprofessional submits via self-service becomes publicly visible in the
+anonymous openbaar register portal — closing the walking-skeleton loop (submit → process → projection
+→ public visibility).
+
+**The path:** self-service submit → BFF → domain → (zaak) OpenZaak → NRC → Event Subscriber →
+projection → openbaar portal reads the BFF's public-safe `GET /openbaar/register`.
+
+```bash
+# 1. Bring the full stack up (self-service :8140, openbaar :8141).
+make up
+
+# 2. Submit a registration via the self-service portal (mock DigiD: jan-burger / test123),
+#    or drive the whole happy path automatically (login → submit → public visibility):
+make verify-e2e
+
+# 3. Open the public register — no login. It lists the submitted entry (id + status only).
+#    Only public-safe fields cross the BFF: bsn / naam never appear.
+open http://localhost:8141/            # search box; searches the BFF by referentie
+curl -fsS http://localhost:8140/openbaar/register | jq   # same public-safe view via the BFF proxy
+# → [ { "id": "<zaak-uuid>", "status": "INGEDIEND" } ]
+```
+
+> The register shows `INGEDIEND` entries today; the approval transition to a terminal status
+> (e.g. `INGESCHREVEN`) lands with the approval flow (S-09b, #75).