✅ Backend v1.2.8

Fix aplicado:

Corregido el acceso a las variables de configuración de MinIO/S3:

backend/app/main.py

@@ -278,7 +278,7 @@ def extract_pdf_text_smart(pdf_content: bytes, max_chars: int = None) -> dict:
         }
 
 
-BACKEND_VERSION = "1.2.7"
+BACKEND_VERSION = "1.2.8"
 app = FastAPI(title="Checklist Inteligente API", version=BACKEND_VERSION)
 
 # S3/MinIO configuration
@@ -3496,13 +3496,13 @@ async def chat_with_ai_assistant(
                     
                     s3_client.upload_fileobj(
                         BytesIO(file_content),
-                        app_config.settings.MINIO_IMAGE_BUCKET,
+                        S3_IMAGE_BUCKET,
                         unique_filename,
                         ExtraArgs={'ContentType': file_type}
                     )
                     
                     # Generar URL
-                    image_url = f"{app_config.settings.MINIO_ENDPOINT}/{app_config.settings.MINIO_IMAGE_BUCKET}/{unique_filename}"
+                    image_url = f"{S3_ENDPOINT}/{S3_IMAGE_BUCKET}/{unique_filename}"
                     file_info['url'] = image_url
                     print(f"🖼️ Imagen subida a S3: {unique_filename}")
                 except Exception as upload_error: