fix(infra): local event-subscriber Acl:BaseUrl parity (closes #94) (#95)

## What & why

Closes #94. The local compose's `event-subscriber` lacked `Acl__BaseUrl` (and the `acl` dependency) that the canonical compose sets (#78) — so it threw `Missing configuration 'Acl:BaseUrl'` and exited on startup, which also knocked over podman-compose's bring-up of the rest of the stack (the frontends were left uncreated). Adds the env + dependency, matching `docker-compose.yml`.

## How verified

Recreated `event-subscriber` from the fixed compose locally — it now starts healthy, and the three portals come up (self-service :8140, openbaar :8141, behandel :8142). `docker compose config` valid.

## Note (separate, not fixed here)

On **rootless podman** the portal→BFF nginx proxy still 502s (`resolver 127.0.0.11` is Docker's embedded DNS; podman uses its own), and podman-compose orchestration of this dependency graph is flaky — both are pre-existing local-engine limitations, clean on Docker Desktop / CI. Tracking separately.

Reviewed-on: #95

infra/docker-compose.local.yml

@@ -380,6 +380,10 @@ services:
     image: register-referentie/event-subscriber:dev
     environment:
       ConnectionStrings__Projection: Host=projection-db;Database=projection;Username=projection;Password=projection
+      # The subscriber enriches the projection with each zaak's reference by asking the ACL — the only
+      # code allowed to read ZGW (§8.1, #78). Required: startup throws without it (parity with the
+      # canonical compose).
+      Acl__BaseUrl: http://acl:8080/
       EventSubscriber__Webhook__AuthToken: ${NOTIFICATION_WEBHOOK_TOKEN:-Bearer big-reference-notifications}
     ports:
       - "8110:8080"
@@ -392,6 +396,8 @@ services:
     depends_on:
       projection-db:
         condition: service_healthy
+      acl:
+        condition: service_healthy
     networks: [cg]
 
   projection-api: