feat: funciones infra — Docker, deploy, build y health check

Funciones impuras para gestión de contenedores: docker_build_image,
docker_compose_up/down, docker_volume_create/list/remove,
generate_dockerfile, write_dockerfile, go_build_binary, health_check_http,
deploy_app y stop_app. Todas con tests unitarios donde aplica.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

functions/infra/docker_compose_up.go

@@ -0,0 +1,22 @@
+package infra
+
+import (
+	"fmt"
+	"os/exec"
+	"strings"
+)
+
+// DockerComposeUp levanta un stack docker-compose desde el archivo dado.
+// Si detach es true ejecuta en background (-d). Retorna el stdout del comando.
+func DockerComposeUp(composeFile string, detach bool) (string, error) {
+	args := []string{"compose", "-f", composeFile, "up"}
+	if detach {
+		args = append(args, "-d")
+	}
+
+	out, err := exec.Command("docker", args...).CombinedOutput()
+	if err != nil {
+		return "", fmt.Errorf("docker compose up %s: %s", composeFile, strings.TrimSpace(string(out)))
+	}
+	return strings.TrimSpace(string(out)), nil
+}