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.

frontend/src/core/mcp/api.ts

@@ -1,4 +1,4 @@
-import { fetchWithAuth } from "@/core/api/fetcher";
+import { fetch } from "@/core/api/fetcher";
 import { getBackendBaseURL } from "@/core/config";
 
 import type { MCPConfig } from "./types";
@@ -9,15 +9,12 @@ export async function loadMCPConfig() {
 }
 
 export async function updateMCPConfig(config: MCPConfig) {
-  const response = await fetchWithAuth(
-    `${getBackendBaseURL()}/api/mcp/config`,
-    {
-      method: "PUT",
-      headers: {
-        "Content-Type": "application/json",
-      },
-      body: JSON.stringify(config),
+  const response = await fetch(`${getBackendBaseURL()}/api/mcp/config`, {
+    method: "PUT",
+    headers: {
+      "Content-Type": "application/json",
     },
-  );
+    body: JSON.stringify(config),
+  });
   return response.json();
 }