fix: correct isStreaming logic when cost is defined

The logic was inverted - when cost is defined in api_req_started, it means the API request has finished (streaming is complete), so should return false, not true.

Author: daniel-lxs

webview-ui/src/components/chat/ChatView.tsx

@@ -558,7 +558,7 @@ const ChatViewComponent: React.ForwardRefRenderFunction<ChatViewRef, ChatViewPro
 
 					// Otherwise, check if cost is defined to determine if streaming is complete
 					if ("cost" in info && info.cost !== undefined) {
-						return true // API request has not finished yet.
+						return false // API request has finished.
 					}
 				}
 			}