feat(tests): add PostgreSQL readiness check in test setup

Makefile

@@ -80,6 +80,16 @@ test-setup: build ## Start test environment (docker-compose/podman-compose)
 		exit 1; \
 	fi
 	@$(COMPOSE_CMD) -f tests/docker-compose.yml up -d
+	@echo "Waiting for PostgreSQL to be ready..."
+	@for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15; do \
+		if $(COMPOSE_CMD) -f tests/docker-compose.yml exec -T postgres pg_isready -U user > /dev/null 2>&1; then \
+			echo "PostgreSQL is ready"; exit 0; \
+		fi; \
+		sleep 2; \
+	done; \
+	echo "ERROR: PostgreSQL did not become ready in time"; \
+	$(COMPOSE_CMD) -f tests/docker-compose.yml logs postgres; \
+	exit 1
 
 test-teardown: ## Stop test environment (docker-compose/podman-compose)
 	@echo "Stopping test environment (using $(COMPOSE_CMD))..."

README.md

@@ -264,6 +264,23 @@ See the [examples](./examples/) directory for complete examples.
 
 ## Docker
 
+### Prebuilt image
+
+Published to `git.warky.dev/wdevs/pgsql-broker` on every `v*.*.*` tag (`.github/workflows/docker-release.yml`), tagged with the version and `latest`.
+
+```bash
+docker pull git.warky.dev/wdevs/pgsql-broker:latest
+docker run --rm -v $(pwd)/broker.yaml:/etc/pgsql-broker/broker.yaml:ro git.warky.dev/wdevs/pgsql-broker:latest
+```
+
+Config must be mounted at `/etc/pgsql-broker/broker.yaml` — no config is baked into the image.
+
+### Building the image locally
+
+```bash
+make docker-build   # builds pgsql-broker:<VERSION> and pgsql-broker:latest via Dockerfile
+```
+
 ### Production: `Dockerfile` + `docker-compose.yml`
 
 Multi-stage build (`golang:1.26-alpine` → `alpine:3.22`, static binary, non-root user). The compose stack runs Postgres, a one-shot `migrate` service (`install --with-roles`), then the `broker` service connecting as `broker_runtime`.