重构 Agent 聊天，支持分支管理与消息克隆

src/hooks/useChatToolActionHandler.ts

@@ -22,18 +22,33 @@ export function useChatToolActionHandler(
   handler: (action: ChatToolAction) => void,
 ) {
   const handlerRef = useRef(handler);
+  const lastHandledSeqRef = useRef(0);
 
   useEffect(() => {
     handlerRef.current = handler;
   }, [handler]);
 
   useEffect(() => {
+    const initialState = useChatToolStore.getState();
+    if (
+      initialState.lastAction &&
+      initialState.actionSeq > lastHandledSeqRef.current &&
+      Date.now() - initialState.lastActionAt < 5000
+    ) {
+      lastHandledSeqRef.current = initialState.actionSeq;
+      handlerRef.current(initialState.lastAction);
+    } else {
+      lastHandledSeqRef.current = initialState.actionSeq;
+    }
+
     const unsubscribe = useChatToolStore.subscribe(
       (state, prevState) => {
         if (
           state.actionSeq !== prevState.actionSeq &&
-          state.lastAction
+          state.lastAction &&
+          state.actionSeq > lastHandledSeqRef.current
         ) {
+          lastHandledSeqRef.current = state.actionSeq;
           handlerRef.current(state.lastAction);
         }
       },