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).

helm/APP_NAME/templates/networkpolicy.yaml

@@ -0,0 +1,66 @@
+{{- if .Values.networkPolicy.enabled }}
+# NetworkPolicy mínima del shape: bajo deny-all-default del namespace, permite:
+# - Ingress: Traefik (web-backend público) + Prometheus (scrape de /metrics).
+# - Egress: DNS, Harbor (pull en startup), ns-addons del tenant (BD).
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: {{ .Release.Name }}
+  labels:
+    {{- include "app.labels" . | nindent 4 }}
+spec:
+  podSelector:
+    matchLabels:
+      {{- include "app.selectorLabels" . | nindent 6 }}
+  policyTypes: [Ingress, Egress]
+
+  ingress:
+    # Tráfico HTTP desde Traefik (IngressRoute)
+    - from:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: traefik-system
+      ports:
+        - protocol: TCP
+          port: 8000
+    # Scrape de métricas Prometheus
+    - from:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: cattle-monitoring-system
+          podSelector:
+            matchLabels:
+              app.kubernetes.io/name: prometheus
+      ports:
+        - protocol: TCP
+          port: 8000
+
+  egress:
+    # DNS
+    - to:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+      ports:
+        - protocol: UDP
+          port: 53
+        - protocol: TCP
+          port: 53
+    # ns-addons del tenant: MariaDB primary + pool
+    - to:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: {{ .Values.networkPolicy.addonsNamespace }}
+      ports:
+        - protocol: TCP
+          port: 3306
+        - protocol: TCP
+          port: 6033
+    # Harbor pull (registro de imágenes)
+    - to:
+        - ipBlock:
+            cidr: 0.0.0.0/0
+      ports:
+        - protocol: TCP
+          port: 443
+{{- end }}