feat: sincronizar scaffold completo del shape web-backend/python

Sincroniza el scaffold canónico desde templates/web-backend-python/ del
repo IDP. Reemplaza el placeholder mínimo previo (.gitea/workflows/ci.yaml,
README.md, .gitignore, catalog-info.yaml) por el scaffold completo
documentado en ADR-053 §3:

- code/ — FastAPI app con /health (db check), /metrics, /demo estático,
  middleware correlation_id, settings Pydantic, db.py con SQLAlchemy
- code/alembic/ — migración inicial vacía + env.py usando MIGRATION_DATABASE_URL
- code/tests/ — pytest + httpx TestClient (test_health, test_demo)
- helm/APP_NAME/ — chart con Deployment, Service, IngressRoute Traefik,
  NetworkPolicy, ServiceMonitor, Job alembic-upgrade como hook
  pre-upgrade,pre-install (backoffLimit: 0)
- coralware-shape.yaml — manifiesto v1alpha1 del contrato del shape
- claim-mariadb.yaml — AddonClaim declarativo (uso futuro ADR-052)
- catalog-info.yaml — entidad Backstage actualizada
- .gitea/workflows/APP_NAME-build.yaml — invoca reusable workflow ADR-038
  + job helm-deploy con KUBECONFIG_TENANT_B64

Placeholders __APP_NAME__, __TIER__, __TENANT_ID__, __TENANT_ID_NODASHES__
serán sustituidos server-side por repo-provisioner cuando materialice el
template para un tenant (pendiente — ADR-053 §11.5).

El openspec/ del golden path NO se sincroniza al repo Gitea (gobernanza
interna de Coralware).

Refs: ADR-052, ADR-053, poc-nexobms.md (PoC NexoBMS Demetrio).

code/tests/conftest.py

@@ -0,0 +1,34 @@
+"""
+Fixtures para los tests del shape.
+
+Levanta una MariaDB efímera con testcontainers para que los tests corran
+contra una BD real (no mocks). El reusable workflow ADR-038 garantiza que
+Docker está disponible en el runner.
+"""
+
+import os
+from collections.abc import Iterator
+
+import pytest
+from fastapi.testclient import TestClient
+from testcontainers.mariadb import MariaDbContainer
+
+
+@pytest.fixture(scope="session")
+def mariadb_url() -> Iterator[str]:
+    """MariaDB efímera por sesión de tests; URL exportada como DATABASE_URL."""
+    with MariaDbContainer("mariadb:11") as mdb:
+        url = mdb.get_connection_url().replace("mysql://", "mysql+pymysql://", 1)
+        os.environ["DATABASE_URL"] = url
+        os.environ["MIGRATION_DATABASE_URL"] = url
+        yield url
+
+
+@pytest.fixture
+def client(mariadb_url: str) -> Iterator[TestClient]:
+    """TestClient con la app cargada contra la BD efímera."""
+    from app.main import create_app
+
+    app = create_app()
+    with TestClient(app) as c:
+        yield c

code/tests/test_demo.py

@@ -0,0 +1,22 @@
+"""Cubre el endpoint /demo: sirve el index estático."""
+from fastapi.testclient import TestClient
+
+
+def test_demo_serves_index_html(client: TestClient) -> None:
+    response = client.get("/demo/")
+    assert response.status_code == 200
+    assert "text/html" in response.headers.get("content-type", "")
+    assert "__APP_NAME__" in response.text or "demo" in response.text.lower()
+
+
+def test_metrics_endpoint_responds(client: TestClient) -> None:
+    response = client.get("/metrics")
+    assert response.status_code == 200
+    assert "text/plain" in response.headers.get("content-type", "")
+
+
+def test_openapi_accessible_when_auth_disabled(client: TestClient) -> None:
+    response = client.get("/openapi.json")
+    assert response.status_code == 200
+    spec = response.json()
+    assert spec["info"]["title"] == "__APP_NAME__"

code/tests/test_health.py

@@ -0,0 +1,30 @@
+"""Cubre el endpoint /health: respuesta 200 con la BD viva, 503 cuando cae."""
+from unittest.mock import patch
+
+from fastapi.testclient import TestClient
+
+
+def test_health_db_up_returns_200(client: TestClient) -> None:
+    response = client.get("/health")
+    assert response.status_code == 200
+    assert response.json() == {"status": "ok", "db": "up"}
+
+
+def test_health_db_down_returns_503(client: TestClient) -> None:
+    with patch("app.main.db_alive", return_value=False):
+        response = client.get("/health")
+    assert response.status_code == 503
+    body = response.json()
+    assert body["status"] == "degraded"
+    assert body["db"] == "down"
+
+
+def test_health_propagates_correlation_id(client: TestClient) -> None:
+    cid = "test-cid-12345"
+    response = client.get("/health", headers={"X-Correlation-ID": cid})
+    assert response.headers.get("X-Correlation-ID") == cid
+
+
+def test_health_generates_correlation_id_when_absent(client: TestClient) -> None:
+    response = client.get("/health")
+    assert response.headers.get("X-Correlation-ID")