feat: Enhance Stream Management with Abort Functionality

- Updated the abort endpoint to support aborting ongoing generation streams using either streamId or conversationId.
- Introduced a new mutation hook `useAbortStreamMutation` for client-side integration.
- Added `useStreamStatus` query to monitor stream status and facilitate resuming conversations.
- Enhanced `useChatHelpers` to incorporate abort functionality when stopping generation.
- Improved `useResumableSSE` to handle stream errors and token refresh seamlessly.
- Updated `useResumeOnLoad` to check for active streams and resume conversations appropriately.

client/src/data-provider/SSE/index.ts

@@ -0,0 +1,2 @@
+export * from './queries';
+export * from './mutations';

client/src/data-provider/SSE/mutations.ts

@@ -0,0 +1,39 @@
+import { useMutation } from '@tanstack/react-query';
+import { request } from 'librechat-data-provider';
+
+export interface AbortStreamParams {
+  /** The stream ID to abort (if known) */
+  streamId?: string;
+  /** The conversation ID to abort (backend will look up the job) */
+  conversationId?: string;
+}
+
+export interface AbortStreamResponse {
+  success: boolean;
+  aborted?: string;
+  error?: string;
+}
+
+/**
+ * Abort an ongoing generation stream.
+ * The backend will emit a `done` event with `aborted: true` to the SSE stream,
+ * allowing the client to handle cleanup via the normal event flow.
+ *
+ * Can pass either streamId or conversationId - backend will find the job.
+ */
+export const abortStream = async (params: AbortStreamParams): Promise<AbortStreamResponse> => {
+  console.log('[abortStream] Calling abort endpoint with params:', params);
+  const result = (await request.post('/api/agents/chat/abort', params)) as AbortStreamResponse;
+  console.log('[abortStream] Abort response:', result);
+  return result;
+};
+
+/**
+ * React Query mutation hook for aborting a generation stream.
+ * Use this when the user explicitly clicks the stop button.
+ */
+export function useAbortStreamMutation() {
+  return useMutation({
+    mutationFn: abortStream,
+  });
+}

client/src/data-provider/SSE/queries.ts

@@ -1,5 +1,6 @@
 import { useQuery } from '@tanstack/react-query';
 import { request } from 'librechat-data-provider';
+import type { Agents } from 'librechat-data-provider';
 
 export interface StreamStatusResponse {
   active: boolean;
@@ -8,6 +9,7 @@ export interface StreamStatusResponse {
   chunkCount?: number;
   aggregatedContent?: Array<{ type: string; text?: string }>;
   createdAt?: number;
+  resumeState?: Agents.ResumeState;
 }
 
 /**
@@ -19,8 +21,12 @@ export const streamStatusQueryKey = (conversationId: string) => ['streamStatus',
  * Fetch stream status for a conversation
  */
 export const fetchStreamStatus = async (conversationId: string): Promise<StreamStatusResponse> => {
-  const response = await request.get(`/api/agents/chat/status/${conversationId}`);
-  return response.data;
+  console.log('[fetchStreamStatus] Fetching status for:', conversationId);
+  const result = await request.get<StreamStatusResponse>(
+    `/api/agents/chat/status/${conversationId}`,
+  );
+  console.log('[fetchStreamStatus] Result:', result);
+  return result;
 };
 
 /**

client/src/data-provider/index.ts

@@ -15,3 +15,4 @@ export * from './queries';
 export * from './roles';
 export * from './tags';
 export * from './MCP';
+export * from './SSE';