feat(infra): containerize BFF + compose-up smoke (refs #29)

Add a multi-stage Dockerfile for the BFF (.NET 10 sdk -> aspnet runtime,
curl for the healthcheck) and infra/docker-compose.yml running it with a
/health healthcheck. `docker compose up --wait` gates on the container
reporting healthy, which is the compose-up smoke test. Document the path
in the README.

Verified: image builds; `docker compose up -d --build --wait` reports the
container Healthy; host curl http://localhost:8080/health -> 200 Healthy.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

BACKLOG.md

@@ -12,22 +12,41 @@ Each slice is **independently demoable** and meets the Definition of Done in `CL
 
 ## Iteration 0 — Foundations *(milestone: `Iteration 0 — Foundations`)*
 
-### S-00 · Repository skeleton, Gitea Actions CI, contributor workflow
+> **S-00 was split** (CLAUDE.md §13) into the sub-slices below. The original
+> outcome — a fresh clone + `docker compose up` reaching a green BFF health
+> endpoint, with CI green and the contributor scaffolding in place — is the sum
+> of S-00-a…e. The Gitea milestones, labels, and slice issues already exist —
+> they are managed directly with the `tea` CLI.
 
-**Outcome:** A fresh `git clone` from the Respellion Gitea remote, followed by `docker compose up`, produces a green "hello world" health endpoint from a placeholder BFF. Gitea Actions runs lint, build, unit tests, and the compose-up smoke test, all green. Issue templates, PR template, milestones, labels, and the first project board exist in Gitea.
+### S-00-a · Placeholder BFF + health endpoint
 
-**Acceptance:**
+**Outcome:** A minimal .NET BFF exposing `GET /health` returning green; runnable with `dotnet run`. TDD anchor for the slice.
 
-- New developer follows `README.md` and reaches a green local environment in under 10 minutes.
-- Gitea Actions pipeline green on `main`.
-- `git-cliff` produces an empty `CHANGELOG.md`.
-- `docs/PRD.md`, `CLAUDE.md`, `BACKLOG.md`, `docs/architecture/adr-0001-loose-coupling.md`, `docs/gitea-workflow.md` all in repo.
-- `.gitea/workflows/ci.yaml`, `.gitea/ISSUE_TEMPLATE/{slice,bug,adr-proposal}.md`, `.gitea/PULL_REQUEST_TEMPLATE.md` all in repo.
-- Gitea milestone `Iteration 1 — Walking Skeleton` exists, populated with issues S-01 through S-09.
+**Touches:** `services/bff/`, tests. **Out of scope:** Docker, CI, OIDC.
 
-**Touches:** repo layout, Gitea Actions workflows, Dockerfile for placeholder BFF, `docker-compose.yml` skeleton, MkDocs scaffold, Gitea issue/PR templates.
+### S-00-b · Dockerfile + compose skeleton + compose-up smoke
 
-**Out of scope:** any business logic, frontend, OpenZaak.
+**Outcome:** BFF containerized; `infra/docker-compose.yml` brings it up; health green within 3 minutes from a fresh clone.
+
+**Touches:** `services/bff/Dockerfile`, `infra/docker-compose.yml`, smoke script. **Out of scope:** other services, CI.
+
+### S-00-c · Gitea Actions CI (lint, build, unit, compose-up smoke)
+
+**Outcome:** `.gitea/workflows/ci.yaml` green on PRs and `main`: lint, build, unit, compose-up smoke. Actions pinned by absolute URL (§8.7/§15).
+
+**Touches:** `.gitea/workflows/ci.yaml`, `docs/runbooks/ci.md`. **Out of scope:** mutation, e2e, container push.
+
+### S-00-d · Contributor workflow: issue/PR templates, git-cliff, CHANGELOG
+
+**Outcome:** Issue templates (`slice`/`bug`/`adr-proposal`), PR template, `git-cliff` → empty `CHANGELOG.md`, `docs/gitea-workflow.md`.
+
+**Touches:** `.gitea/ISSUE_TEMPLATE/`, `.gitea/PULL_REQUEST_TEMPLATE.md`, `cliff.toml`, `CHANGELOG.md`, `docs/gitea-workflow.md`. **Out of scope:** app code.
+
+### S-00-e · Docs scaffold: MkDocs + ADR-0001 + README quickstart
+
+**Outcome:** MkDocs builds the `docs/` site; `docs/architecture/adr-0001-loose-coupling.md` exists; README has a sub-10-minute quickstart.
+
+**Touches:** `mkdocs.yml`, `docs/` nav, `docs/architecture/adr-0001-loose-coupling.md`, `README.md`. **Out of scope:** Gitea Pages publish.
 
 ---
 

README.md

@@ -56,6 +56,15 @@ docker compose -f infra/docker-compose.yml up -d
 
 Health checks should be green within ~3 minutes on a developer machine. If something fails, see [docs/runbooks/local-startup.md](docs/runbooks/local-startup.md).
 
+> **Wired today (Iteration 0):** only the placeholder BFF is in `infra/docker-compose.yml` so far. Bring it up and smoke-test its health endpoint:
+>
+> ```bash
+> docker compose -f infra/docker-compose.yml up -d --build --wait
+> curl http://localhost:8080/health   # -> Healthy
+> ```
+>
+> `--wait` exits non-zero unless the container reports healthy, so this doubles as the compose-up smoke test. The remaining services and the URLs below land in later slices.
+
 **Default URLs**
 
 | Service | URL |

infra/docker-compose.yml

@@ -0,0 +1,19 @@
+# Local development stack. Grows service-by-service with each slice.
+# S-00-b: the placeholder BFF with a /health check.
+#
+#   docker compose -f infra/docker-compose.yml up -d --build --wait
+#   curl http://localhost:8080/health   # -> Healthy
+services:
+  bff:
+    build:
+      context: ../services/bff
+      dockerfile: Dockerfile
+    image: register-referentie/bff:dev
+    ports:
+      - "8080:8080"
+    healthcheck:
+      test: ["CMD", "curl", "-fsS", "http://localhost:8080/health"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+      start_period: 10s

services/bff/.dockerignore

@@ -0,0 +1,3 @@
+**/bin
+**/obj
+**/*.user

services/bff/Dockerfile

@@ -0,0 +1,30 @@
+# Multi-stage build for the placeholder BFF (.NET 10).
+# Build context is services/bff (see infra/docker-compose.yml).
+FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
+WORKDIR /src
+
+# Restore first (cached unless the csproj changes).
+COPY Bff.Api/Bff.Api.csproj Bff.Api/
+RUN dotnet restore Bff.Api/Bff.Api.csproj
+
+# Then build + publish.
+COPY Bff.Api/ Bff.Api/
+RUN dotnet publish Bff.Api/Bff.Api.csproj -c Release -o /app/publish /p:UseAppHost=false
+
+FROM mcr.microsoft.com/dotnet/aspnet:10.0 AS runtime
+WORKDIR /app
+
+# curl is used by the container HEALTHCHECK / compose healthcheck.
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends curl \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY --from=build /app/publish .
+
+ENV ASPNETCORE_URLS=http://+:8080
+EXPOSE 8080
+
+HEALTHCHECK --interval=5s --timeout=3s --start-period=10s --retries=5 \
+    CMD curl -fsS http://localhost:8080/health || exit 1
+
+ENTRYPOINT ["dotnet", "Bff.Api.dll"]