refactor(webui): shrink fork implementation

webui/src/components/thread/ThreadComposer.tsx

@@ -172,7 +172,6 @@ interface ThreadComposerProps {
   workspaceError?: string | null;
   onWorkspaceScopeChange?: (scope: WorkspaceScopePayload) => void;
   pendingQueueKey?: string | null;
-  externalError?: string | null;
 }
 
 const COMMAND_ICONS: Record<string, LucideIcon> = {
@@ -766,7 +765,6 @@ export function ThreadComposer({
   workspaceError = null,
   onWorkspaceScopeChange,
   pendingQueueKey = null,
-  externalError = null,
 }: ThreadComposerProps) {
   const { t } = useTranslation();
   const [value, setValue] = useState("");
@@ -1149,10 +1147,6 @@ export function ThreadComposer({
     });
   }, [clear, pendingQueueKey]);
 
-  useEffect(() => {
-    if (externalError) setInlineError(externalError);
-  }, [externalError]);
-
   const appendTranscription = useCallback((text: string) => {
     const transcript = text.trim();
     if (!transcript) return;