Refactor API fetch calls to use a unified fetch function; enhance chat history loading with new hooks and UI components

- Replaced `fetchWithAuth` with a generic `fetch` function across various API modules for consistency.
- Updated `useThreadStream` and `useThreadHistory` hooks to manage chat history loading, including loading states and pagination.
- Introduced `LoadMoreHistoryIndicator` component for better user experience when loading more chat history.
- Enhanced message handling in `MessageList` to accommodate new loading states and history management.
- Added support for run messages in the thread context, improving the overall message handling logic.
- Updated translations for loading indicators in English and Chinese.

backend/packages/harness/deerflow/agents/middlewares/summarization_middleware.py

@@ -0,0 +1,13 @@
+from typing import override
+
+from langchain.agents.middleware import SummarizationMiddleware as BaseSummarizationMiddleware
+from langchain_core.messages.human import HumanMessage
+
+
+class SummarizationMiddleware(BaseSummarizationMiddleware):
+    @override
+    def _build_new_messages(self, summary: str) -> list[HumanMessage]:
+        """Override the base implementation to let the human message with the special name 'summary'.
+        And this message will be ignored to display in the frontend, but still can be used as context for the model.
+        """
+        return [HumanMessage(content=f"Here is a summary of the conversation to date:\n\n{summary}", name="summary")]