feat: poblar scaffold inicial del shape rest-api/python

Reemplaza el placeholder mínimo previo por el scaffold canónico del
golden path rest-api/python (entry point para tier free-trial):

- code/app/main.py — FastAPI con /health (sin DB), /metrics, middleware
  correlation_id, settings Pydantic
- code/tests/ — pytest + httpx TestClient (sin testcontainers, sin Docker)
- helm/APP_NAME/ — chart minimal: Deployment, Service, IngressRoute,
  NetworkPolicy. SIN Job Alembic, SIN ServiceMonitor, SIN claim de BD
- coralware-shape.yaml — shapeVersion 1.0.0, minTier free-trial,
  promotionPath -> web-backend-python cuando se requiera persistencia
- .gitea/workflows/APP_NAME-build.yaml — invoca reusable workflow ADR-038
  + job helm-deploy con KUBECONFIG_TENANT_B64

Diferencias con web-backend/python: sin alembic, sin BD, sin
testcontainers, NetworkPolicy sin acceso a ns-addons.

Placeholders __APP_NAME__, __TIER__, __TENANT_ID__, __TENANT_ID_NODASHES__
serán sustituidos server-side por repo-provisioner.

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

Refs: ADR-027 (Golden Paths), ADR-038 (CI), ADR-053 (referencia anatomía).

code/tests/conftest.py

@@ -0,0 +1,21 @@
+"""
+Fixtures para los tests del shape rest-api/python.
+
+A diferencia de web-backend/python (que levanta MariaDB con testcontainers),
+este shape no tiene persistencia — los tests corren sin Docker.
+"""
+
+from collections.abc import Iterator
+
+import pytest
+from fastapi.testclient import TestClient
+
+
+@pytest.fixture
+def client() -> Iterator[TestClient]:
+    """TestClient con la app cargada. Sin BD, sin contenedores externos."""
+    from app.main import create_app
+
+    app = create_app()
+    with TestClient(app) as c:
+        yield c

code/tests/test_main.py

@@ -0,0 +1,26 @@
+"""Cubre los endpoints obligatorios del shape: /health y /metrics."""
+
+from fastapi.testclient import TestClient
+
+
+def test_health_returns_200_ok(client: TestClient) -> None:
+    response = client.get("/health")
+    assert response.status_code == 200
+    assert response.json() == {"status": "ok"}
+
+
+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")
+
+
+def test_metrics_endpoint_serves_prometheus_format(client: TestClient) -> None:
+    response = client.get("/metrics")
+    assert response.status_code == 200
+    assert "text/plain" in response.headers.get("content-type", "")