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/health_check_http.go

@@ -0,0 +1,38 @@
+package infra
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+)
+
+// HealthCheckHTTP hace polling HTTP GET a url hasta recibir status 200
+// o hasta que pasen timeoutSecs segundos. Entre intentos espera intervalMs milisegundos.
+func HealthCheckHTTP(url string, timeoutSecs, intervalMs int) error {
+	deadline := time.Now().Add(time.Duration(timeoutSecs) * time.Second)
+	interval := time.Duration(intervalMs) * time.Millisecond
+
+	client := &http.Client{
+		Timeout: time.Duration(intervalMs)*time.Millisecond + 500*time.Millisecond,
+	}
+
+	var lastErr error
+	for time.Now().Before(deadline) {
+		resp, err := client.Get(url)
+		if err == nil {
+			resp.Body.Close()
+			if resp.StatusCode == http.StatusOK {
+				return nil
+			}
+			lastErr = fmt.Errorf("status %d", resp.StatusCode)
+		} else {
+			lastErr = err
+		}
+		time.Sleep(interval)
+	}
+
+	if lastErr != nil {
+		return fmt.Errorf("health check %s timeout after %ds: %w", url, timeoutSecs, lastErr)
+	}
+	return fmt.Errorf("health check %s timeout after %ds", url, timeoutSecs)
+}