feat(infra): wire OpenZaak → Open Notificaties notifications (refs #56)

Completes the S-01-c wiring so a zaak created in OpenZaak is published to NRC:

- OpenZaak: a zgw_consumers 'nrc' service + notifications_config (setup_configuration),
  publishing as big-reference-seed. NOTIFICATIONS_DISABLED stays true for OpenZaak-only
  bring-ups (OZ_NOTIFICATIONS_DISABLED) so the ACL integration test doesn't 500; the
  full/local stacks and stack-up set it false.
- NRC: the JWT credential, an 'ac' service + autorisaties_api delegation to OpenZaak's
  Autorisaties API, and the 'zaken' kanaal. nrc-init now runs setup_configuration; its
  data.yaml is delivered via the rr-nrc-config volume (seed-config.sh nrc), mirroring oz.
- nrc-beat added to every stack: NRC accepts a notification then drains it via a
  scheduled execute_notifications task — without beat, nothing is delivered. Interval 5s.

Applied across the standalone, full, and local-bind-mount composes.

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

infra/opennotificaties/setup_configuration/data.yaml

@@ -1,5 +1,41 @@
-# Open Notificaties setup_configuration.
-# Stage 1 (this commit): intentionally minimal — the init container runs
-# migrations; no steps enabled yet. The OpenZaak<->NRC notification wiring
-# (Services, Authorization, JWT, Kanalen) is added next. See ADR-0002 / S-01-c.
-{}
+# Open Notificaties (NRC) setup_configuration (S-01-c, #56).
+# Wires NRC so OpenZaak can publish notifications:
+#  - the JWT credential OpenZaak authenticates with,
+#  - delegation of authorization checks to OpenZaak's Autorisaties API (AC),
+#  - the `zaken` kanaal OpenZaak publishes zaak events on.
+# Dev-only credentials — not for production. Steps from nrc.setup_configuration.
+
+# 1. JWT credential NRC uses to verify the token OpenZaak presents.
+vng_api_common_credentials_config_enable: true
+vng_api_common_credentials:
+  items:
+    - identifier: big-reference-seed
+      secret: insecure-dev-secret-change-me
+
+# 2. The Autorisaties API (OpenZaak's AC) NRC consults to authorize publishers.
+zgw_consumers_config_enable: true
+zgw_consumers:
+  services:
+    - identifier: openzaak-ac
+      label: OpenZaak Autorisaties API
+      api_type: ac
+      api_root: http://openzaak:8000/autorisaties/api/v1/
+      auth_type: zgw
+      client_id: big-reference-seed
+      secret: insecure-dev-secret-change-me
+
+# 3. Delegate authorization to that AC.
+autorisaties_api_config_enable: true
+autorisaties_api:
+  authorizations_api_service_identifier: openzaak-ac
+
+# 4. The kanaal OpenZaak publishes zaak events on.
+notifications_kanalen_config_enable: true
+notifications_kanalen_config:
+  items:
+    - naam: zaken
+      documentatie_link: https://github.com/VNG-Realisatie/gemma-zaken
+      filters:
+        - bronorganisatie
+        - zaaktype
+        - vertrouwelijkheidaanduiding