feat(base_step): set default language from app context when not provided (#269)

- Initialize language attribute with app context language if not explicitly set
- Add conditional logic to check for existing language value before assignment
- Ensure proper fallback behavior when language parameter is empty or None

reme4/config/default.yaml

@@ -418,7 +418,7 @@ components:
 
   as_llm_formatter:
     default:
-      backend: ${LLM_FORMATTER_BACKEND:-anthropic}
+      backend: ${LLM_BACKEND:-anthropic}
 
   file_graph:
     default:

reme4/steps/base_step.py

@@ -125,6 +125,8 @@ class BaseStep(ComponentMixin, ABC):
     ):
         super().__init__(name=name, backend=backend, app_context=app_context, **kwargs)
         self.language: str = language
+        if not self.language and self.app_context is not None:
+            self.language = self.app_context.app_config.language
         self.input_mapping = input_mapping
         self.output_mapping = output_mapping
         self.context: RuntimeContext | None = None