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).

coralware-shape.yaml

@@ -0,0 +1,28 @@
+apiVersion: coralware.cloud/v1alpha1
+kind: Shape
+metadata:
+  name: rest-api-python
+spec:
+  goldenPath: rest-api
+  goldenPathLang: python
+  shapeVersion: "1.0.0"
+  minTier: free-trial
+  app:
+    name: __APP_NAME__
+    framework: fastapi
+    pythonVersion: "3.12"
+  endpoints:
+    health: /health
+    docs: /docs
+    openapi: /openapi.json
+    metrics: /metrics
+  database:
+    required: false
+  migrations:
+    tool: none
+  observability:
+    metricsPort: 9090
+    prometheusScrape: false
+  promotionPath:
+    nextShape: web-backend-python
+    reason: cuando-la-app-necesita-persistencia