Studio: fix edit/run UI and write worldbook on advance (R6)

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/Studio/StudioRunPage.jsx

@@ -515,7 +515,6 @@ function StudioRunPage() {
   const [chatInput, setChatInput] = useState('');
   const [streamOutput, setStreamOutput] = useState(false);
   const [toolOptionIndex, setToolOptionIndex] = useState(0);
-  const [pendingUserText, setPendingUserText] = useState(null);
   const [runListExpanded, setRunListExpanded] = useState(false);
   const [renamingId, setRenamingId] = useState(null);
   const [renameValue, setRenameValue] = useState('');
@@ -534,7 +533,6 @@ function StudioRunPage() {
     setRunSessionEntered(false);
     setInsertionPopupOpen(false);
     setContextBlockPopup(null);
-    setPendingUserText(null);
   }, [currentRunId, runProjectId, setRunSessionEntered]);
 
   const activeNodeState = useMemo(() => {
@@ -621,11 +619,9 @@ function StudioRunPage() {
   const handleChatSend = async (text) => {
     if (!text || isInitBindActive || !isWorldbookActive || runMessaging) return;
 
-    setPendingUserText(text);
     setChatInput('');
 
     const run = await sendRunMessage(text, { stream: streamOutput });
-    setPendingUserText(null);
     if (!run) {
       /* error surfaced via runError */
     }
@@ -649,7 +645,6 @@ function StudioRunPage() {
     if (run) {
       setChatInput('');
       setToolOptionIndex(0);
-      setPendingUserText(null);
     }
   };
 
@@ -864,7 +859,6 @@ function StudioRunPage() {
           stepMessages={stepMessages}
           thinking={runStreamingThinking ?? lastToolResponse?.thinking}
           evaluation={runStreamingThinking ? null : lastToolResponse?.evaluation}
-          pendingUserText={pendingUserText}
           inputValue={chatInput}
           onInputChange={setChatInput}
           onSend={handleChatSend}