feat(FN-3608): update dashboard chat documentation

Updated the dashboard chat documentation in the user guide with a minor addition.

Fusion-Task-Id: FN-3608

.changeset/chat-stream-stuck-state.md

@@ -0,0 +1,10 @@
+---
+"@runfusion/fusion": patch
+---
+
+Fix chat sending silently failing on flaky networks (especially mobile).
+The SSE reader in the dashboard client now treats a closed stream without
+a terminal `done`/`error` event as an error so streaming state unwinds
+instead of getting stuck. The `useChat` and `useQuickChat` hooks also now
+show a toast when a message is queued behind an in-flight response, so
+the previous stuck state is observable rather than silent.

packages/dashboard/app/api/legacy.ts

@@ -8058,6 +8058,7 @@ export function streamChatResponse(
 
   const abortController = new AbortController();
   let closedByUser = false;
+  let terminated = false;
 
   const dispatchEvent = (eventName: string, rawData: string): void => {
     if (!eventName) {
@@ -8101,6 +8102,7 @@ export function streamChatResponse(
         }
         break;
       case "done":
+        terminated = true;
         try {
           const parsed = JSON.parse(rawData) as { messageId?: unknown; message?: unknown };
           handlers.onDone?.({
@@ -8112,6 +8114,7 @@ export function streamChatResponse(
         }
         break;
       case "error":
+        terminated = true;
         try {
           const parsed = JSON.parse(rawData);
           handlers.onError?.(parsed.message || parsed);
@@ -8216,6 +8219,14 @@ export function streamChatResponse(
 
         processLines(decoder.decode(value, { stream: true }));
       }
+
+      // Server closed the stream without emitting a terminal `done` or `error`
+      // SSE event (common on flaky mobile networks, proxy idle-kill, or
+      // backgrounded tabs). Surface as an error so the client unwinds
+      // streaming state instead of getting stuck with isStreaming=true.
+      if (!terminated && !closedByUser) {
+        handlers.onError?.("Connection closed unexpectedly");
+      }
     } catch (err: unknown) {
       if (err instanceof DOMException && err.name === "AbortError") {
         if (!closedByUser) {

packages/dashboard/app/hooks/useChat.ts

@@ -492,6 +492,7 @@ export function useChat(
       if (isStreaming) {
         pendingMessageRef.current = content;
         setPendingMessage(content);
+        addToast?.("Still waiting for previous response — message queued", "warning");
         return;
       }
 

packages/dashboard/app/hooks/useQuickChat.ts

@@ -557,6 +557,7 @@ export function useQuickChat(
 
         pendingMessageRef.current = content;
         setPendingMessage(content);
+        addToast?.("Still waiting for previous response — message queued", "warning");
         return Promise.resolve();
       }