fix(infra): docker-compose.local self-seeds zaaktype, DMN + NRC abonnement (closes #110) (#114)

## What & why

The host-browser stack (`make local`) had drifted behind three slices, so a fresh bring-up couldn't complete the flow: registrations stuck at `OpenZaakAanmaken`, the behandel werkbak stayed empty, and the openbaar register showed nothing. The `verify-*` scripts do this setup for CI at test time; `make local` had no equivalent.

This makes the local stack **self-seed at bring-up** so it just works in a browser:

- **DMN** — `flowable-init` now also deploys `diploma-eligibility.dmn` (was BPMN-only), so completing `WachtOpDocumenten` routes through the DMN to `Beoordelen` instead of 404ing.
- **Zaaktype + ACL** — a `local-seed` one-shot publishes the BIG zaaktype (whose UUID is server-assigned, hence not static in the compose file) and writes the real URLs to `seed-env:/acl.env`; the ACL sources it on startup via an entrypoint override.
- **NRC abonnement** — an `nrc-subscribe` one-shot registers the `zaken` subscription at the event-subscriber callback, so notifications reach the projection/openbaar register.

Both one-shots reach OpenZaak/NRC by **container IP** (a single-label host fails their Django URLValidator), mirroring the CI verify scripts. Design + trade-offs in **ADR-0020**.

Closes #110

## Definition of Done

- [x] Linked Gitea issue (#110).
- [x] Failing test committed before the implementation — `test(infra): …` adds `infra/run-local-flow-check.sh` / `make verify-local`; the three gaps' failures were observed live on a fresh `make local` (red), and the fix turns it green.
- [x] Implementation makes the test pass; docs commit follows.
- [x] Conventional Commits referencing the issue (`refs #110`).
- [ ] CI green — running on the restored runner. Infra-only change; the CI `verify-stack` job uses `docker-compose.yml` (untouched). Also validated locally: `make verify-local` passes against a fresh `make local` (see below).
- [x] `docker compose up` from a fresh clone reaches green health checks — verified: `make local` healthy in ~2m20s, then `make verify-local` green.
- [x] Docs updated — ADR-0020 + demo-script note.
- [x] ADR added in `docs/architecture/` — ADR-0020.
- [x] Demo note in `docs/demo-script.md`.

## Notes for reviewers

- **Infra-only** — no service code changes; the ACL image and the CI stack (`docker-compose.yml`) are untouched.
- **Verified end-to-end on a fresh stack** (`make local-down && make local && make verify-local`):
  ```
  >> 2. zaak opened            (zaaktype seeded + wired)
  >> 3. documents accepted 204 (DMN deployed)
  >> 4. in the werkbak         (DMN routing → Beoordelen)
  >> 5. visible in the openbaar register (NRC abonnement)
  OK — a fresh local stack completed the flow with no manual seeding
  ```
- **Follow-up:** the cleaner design — ACL resolving its zaaktype by `identificatie` instead of a pinned server-assigned URL — is split out as **S-27 (#113)**; landing it would remove the `acl.env` injection here. ADR-0020 records this.
- The `seed-env` volume carries the generated `acl.env` from `local-seed` to the ACL; a `down --volumes` (as `make local-down` does) resets it cleanly.

Reviewed-on: #114

Makefile

@@ -43,7 +43,7 @@ export DOCKER_HOST := unix://$(PODMAN_SOCK)
 endif
 endif
 
-.PHONY: ci lint build unit mutation frontend integration verify verify-up verify-acl verify-nrc verify-projection verify-bff verify-domain verify-notifications smoke up down local local-down changelog openzaak-up openzaak-smoke openzaak-seed openzaak-down stack-up stack-smoke stack-down keycloak-up keycloak-smoke keycloak-down flowable-up flowable-smoke flowable-down help
+.PHONY: ci lint build unit mutation frontend integration verify verify-up verify-acl verify-nrc verify-projection verify-bff verify-domain verify-notifications smoke up down local verify-local local-down changelog openzaak-up openzaak-smoke openzaak-seed openzaak-down stack-up stack-smoke stack-down keycloak-up keycloak-smoke keycloak-down flowable-up flowable-smoke flowable-down help
 
 ## ci: run the full pipeline — lint, build, unit, mutation, frontend, verify (mirrors Gitea Actions)
 ## `verify` is the live-stack stage (full stack up once → ACL + notification checks).
@@ -114,6 +114,11 @@ local:
 	docker compose -f $(LOCAL_COMPOSE) up -d --build
 	WAIT_TIMEOUT=420 bash infra/wait-healthy.sh $(WAIT_SVCS)
 
+## verify-local: acceptance check for the local stack (S-B04) — a fresh `make local` completes the
+## whole flow (zaaktype seeded + DMN deployed + NRC abonnement) with NO manual seeding.
+verify-local:
+	bash infra/run-local-flow-check.sh
+
 ## local-down: stop and remove the bind-mount stack
 local-down:
 	docker compose -f $(LOCAL_COMPOSE) down --volumes