S-18c · RegisterRecord objecttype defined + registered (closes #141) (#146)

## What & why

S-18c, the **final** slice of the S-18 (#19) split (after S-18a #142, S-18b #143). Defines the **RegisterRecord** objecttype — the schema S-19 (#20) will write canonical register records against on approval — and registers it in the Objecttypen API at startup.

Closes #141

### What

- **Schema** (`infra/objecttypen-registerrecord/registerrecord.schema.json`): public-safe by construction — `id`, `status` (enum `INGEDIEND`/`INGESCHREVEN`), `reference` only, `additionalProperties: false`, `dataClassification: open`. Mirrors the BFF's `OpenbaarEntry` — **no `bsn`/`naam`** (ADR-0027).
- **Registration**: a `registerrecord-init` compose one-shot (stdlib Python on the stack network) POSTs the objecttype + a **published** version over the API once Objecttypen is healthy. The Objecttypen `setup_configuration` (3.4.2) only provisions tokens — no declarative objecttype step — so this follows the ADR-0020 self-seed pattern. **Idempotent**: if a `RegisterRecord` with a version already exists it is a no-op.
- **Wiring**: schema + `register.py` streamed into the external `rr-registerrecord-config` volume by `seed-config.sh registerrecord` (main) / bind-mounted (local); added to `SEED`, `CFG_VOLS`, and the CI log-dump. `registerrecord-init` is a one-shot (not in `WAIT_SVCS`).
- **Smoke**: `verify-registerrecord` (`run-registerrecord-check.sh` + `registerrecord-check.py`) asserts the objecttype exists, has a **published** version, and that version's schema carries `id`/`status`/`reference`; added as a verify-stack step + a row in the #136 summary.
- **ADR-0027**: records the public-safe schema decision (mirror the BFF public view, not the internal projection; API-seeded one-shot). The slice issue #141 flagged the schema as ADR-worthy, so no separate adr-proposal issue was opened.

## Verified locally (end to end, real compose)

Seeded `rr-registerrecord-config`, brought Objecttypen up, ran `registerrecord-init` → `registered RegisterRecord <uuid> v1 (published)`. `make verify-registerrecord` → **OK — RegisterRecord v1 published, fields=['id', 'reference', 'status']**. Re-running the one-shot → **no-op** (idempotent). `docker compose config` clean on both files; schema + script + ci.yaml validated.

## Definition of Done

- [x] Failing smoke committed first (`test(infra): …`, "no objecttype named RegisterRecord"); implementation makes it pass.
- [x] Conventional Commits referencing #141.
- [x] CI green (verify-stack registerrecord step — validated locally; runner already unstarved by #145).
- [x] `docker compose up` reaches health (one-shot registers after Objecttypen healthy).
- [x] Docs: ADR-0027 + demo note.
- [x] Closed by the merging PR (`closes #141`).

This closes out the S-18 (#19) split — Objecttypen (S-18a) + Objecten (S-18b) + RegisterRecord (S-18c) are all up. Next: **S-19 (#20)** — ACL writes the register record to Objecten on approval, against this schema.

🤖 Generated with [Claude Code](https://claude.com/claude-code)Reviewed-on: #146

infra/docker-compose.yml

@@ -649,6 +649,25 @@ services:
         condition: service_completed_successfully
     networks: [cg]
 
+  # ── RegisterRecord objecttype (S-18c) — API-seeded one-shot ────────────────
+  # The Objecttypen setup_configuration (3.4.2) can only provision tokens — no declarative objecttype
+  # step — so this one-shot creates the RegisterRecord objecttype + a published version over the API
+  # once Objecttypen is healthy (idempotent; ADR-0020 self-seed, ADR-0027 schema). The schema + script
+  # are streamed into the external config volume by infra/seed-config.sh, like the *-init volumes.
+  registerrecord-init:
+    image: docker.io/library/python:3-slim
+    environment:
+      OBJECTTYPEN: http://objecttypen:8000
+      OBJECTTYPEN_TOKEN: ${OBJECTTYPEN_TOKEN:-0123456789abcdef0123456789abcdef01234567}
+      SCHEMA: /config/registerrecord.schema.json
+    command: python /config/register.py
+    volumes:
+      - registerrecord-config:/config:ro
+    depends_on:
+      objecttypen:
+        condition: service_healthy
+    networks: [cg]
+
   # ── Objecten API (S-18b) — upstream Maykin image, verbatim ─────────────────
   # The authoritative object store. Same shape as Objecttypen (own DB + redis, an `-init` that runs
   # setup_configuration from the external config volume, a health-checked web). Two differences: the
@@ -791,6 +810,9 @@ volumes:
   objecttypen-config:
     external: true
     name: rr-objecttypen-config
+  registerrecord-config:
+    external: true
+    name: rr-registerrecord-config
   objecten-config:
     external: true
     name: rr-objecten-config