fix: use python health check inside container (no curl/wget in image)

.gitea/workflows/deploy.yml

@@ -32,7 +32,7 @@ jobs:
         run: |
           echo "Waiting for backend..."
           for i in $(seq 1 30); do
-            curl -sf http://localhost:5137/api/health > /dev/null 2>&1 && echo "✓ Backend healthy" && break
+            docker exec cohorta-backend-1 python3 -c "import urllib.request; urllib.request.urlopen('http://localhost:5137/api/health')" 2>/dev/null && echo "✓ Backend healthy" && break
             sleep 3
           done
           docker compose -f /opt/03-business/cohorta/docker-compose.yml ps