feat(infra): subscribe the projection to the objecten kanaal (refs #153)

Completes the re-source (ADR-0030): the Event Subscriber's abonnement moves from `zaken` to
`objecten`, in both the local stack's `nrc-subscribe` and the CI projection check. The
OpenZaak → NRC check keeps its own `zaken` abonnement — OpenZaak still publishes, nothing
in the product listens.

- register-abonnement.py subscribes to `objecten`, and now treats the kanaal as part of
  "already current" — an abonnement left from before this slice points at the right callback
  but the wrong kanaal, and would never have been replaced on IP alone.
- run-projection-check.sh opens its zaak *through the ACL* instead of straight against
  OpenZaak, because the ACL is what writes the register record the projection is now derived
  from. A zaak created behind the ACL's back produces no row — which is the re-source working.
- The acceptance scenario is restated in register terms and gains the approval case: the same
  row moving INGEDIEND → INGESCHREVEN is now one registration's record being updated, not two
  unrelated ZGW events.

infra/local/register-abonnement.py

@@ -2,10 +2,10 @@
 """Local-stack bootstrap (S-B04, #110, ADR-0020) — register the NRC abonnement.
 
 Runs as the `nrc-subscribe` init container of infra/docker-compose.local.yml. Registers an
-abonnement on the `zaken` kanaal pointing at the event-subscriber's /notifications callback, so
-OpenZaak's notifications (zaak create + status set) reach the projection — without this the openbaar
-(public) register stays empty. This is what infra/verify-notification-driver.py does for CI (minus
-the test zaak it also creates).
+abonnement on the `objecten` kanaal pointing at the event-subscriber's /notifications callback, so
+the register writes the ACL makes (INGEDIEND on submit, INGESCHREVEN on approval) reach the
+projection — without this the openbaar (public) register stays empty. Since S-19b-2 the projection
+is sourced from the register in Objecten, not from ZGW zaak events (ADR-0030).
 
 The callback host is the event-subscriber's resolved **container IP**, not `event-subscriber`, because
 NRC validates callbackUrl with Django's URLValidator (a single-label host is rejected — same reason the
@@ -22,6 +22,8 @@ SINK_PORT = os.environ.get("SINK_PORT", "8080")
 SINK_AUTH = os.environ.get("SINK_AUTH", "Bearer big-reference-notifications")
 CID = os.environ.get("OZ_CLIENT_ID", "big-reference-seed")
 SECRET = os.environ.get("OZ_SECRET", "insecure-dev-secret-change-me")
+# The projection is sourced from the register in Objecten, not from ZGW zaak events (S-19b-2).
+KANAAL = "objecten"
 
 
 def token():
@@ -60,7 +62,10 @@ def main():
     status, body = call("GET", f"{NRC}/api/v1/abonnement")
     for ab in (body or []) if status == 200 else []:
         if str(ab.get("callbackUrl", "")).endswith("/notifications"):
-            if ab.get("callbackUrl") == callback:
+            # The kanaal is part of "current": an abonnement left over from before S-19b-2 points at
+            # the right callback but listens on `zaken`, and would never be replaced on IP alone.
+            kanalen = [k.get("naam") for k in ab.get("kanalen", [])]
+            if ab.get("callbackUrl") == callback and kanalen == [KANAAL]:
                 print(f"abonnement already current: {ab['url']}")
                 return
             call("DELETE", ab["url"])
@@ -68,7 +73,7 @@ def main():
 
     status, ab = call("POST", f"{NRC}/api/v1/abonnement", {
         "callbackUrl": callback, "auth": SINK_AUTH,
-        "kanalen": [{"naam": "zaken", "filters": {}}]})
+        "kanalen": [{"naam": KANAAL, "filters": {}}]})
     if status != 201:
         sys.exit(f"create abonnement -> {status}: {json.dumps(ab)}")
     print(f"abonnement registered: {ab['url']} -> {callback}")