chore: Update default base image to UCloud registry with latest tag.

Author: mfzzf

ucloud_sandbox/template/main.py

@@ -737,7 +737,7 @@ def __init__(
         :param file_context_path: Base path for resolving relative file paths in copy operations
         :param file_ignore_patterns: List of glob patterns to ignore when copying files
         """
-        self._default_base_image: str = "e2bdev/base"
+        self._default_base_image: str = "uhub.service.ucloud.cn/agentbox/e2bdev/base:latest"
         self._base_image: Optional[str] = self._default_base_image
         self._base_template: Optional[str] = None
         self._registry_config: Optional[RegistryConfig] = None