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/agents/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 { Agent, CreateAgentRequest, UpdateAgentRequest } from "./types";
@@ -29,7 +29,7 @@ export async function getAgent(name: string): Promise<Agent> {
 }
 
 export async function createAgent(request: CreateAgentRequest): Promise<Agent> {
-  const res = await fetchWithAuth(`${getBackendBaseURL()}/api/agents`, {
+  const res = await fetch(`${getBackendBaseURL()}/api/agents`, {
     method: "POST",
     headers: { "Content-Type": "application/json" },
     body: JSON.stringify(request),
@@ -45,7 +45,7 @@ export async function updateAgent(
   name: string,
   request: UpdateAgentRequest,
 ): Promise<Agent> {
-  const res = await fetchWithAuth(`${getBackendBaseURL()}/api/agents/${name}`, {
+  const res = await fetch(`${getBackendBaseURL()}/api/agents/${name}`, {
     method: "PUT",
     headers: { "Content-Type": "application/json" },
     body: JSON.stringify(request),
@@ -58,7 +58,7 @@ export async function updateAgent(
 }
 
 export async function deleteAgent(name: string): Promise<void> {
-  const res = await fetchWithAuth(`${getBackendBaseURL()}/api/agents/${name}`, {
+  const res = await fetch(`${getBackendBaseURL()}/api/agents/${name}`, {
     method: "DELETE",
   });
   if (!res.ok) throw new Error(`Failed to delete agent: ${res.statusText}`);