fix: 重置按钮放在头部，返回按钮的逻辑不变

frontend/src/app/workspace/agents/[agent_name]/chats/[thread_id]/page.tsx

@@ -166,7 +166,6 @@ export default function AgentChatPage() {
                   threadId={threadId}
                   autoFocus={isNewThread}
                   showWelcomeStyle={isNewThread}
-                  hasSubmitted={!isNewThread}
                   status={
                     thread.error
                       ? "error"

frontend/src/app/workspace/chats/[thread_id]/page.tsx

@@ -233,7 +233,6 @@ export default function ChatPage() {
     [thread.values.artifacts],
   );
 
-  const [hasSubmitted, setHasSubmitted] = useState(false);
   const [historyCutoff, setHistoryCutoff] = useState<number | null>(null);
 
   useEffect(() => {
@@ -241,7 +240,6 @@ export default function ChatPage() {
       setHistoryCutoff(null);
       return;
     }
-    if (hasSubmitted) return;
     // Welcome 态下、未提交前，把当前已有消息都当作“历史”切掉。
     // 这样即使历史消息是后续异步补齐，也不会重新露出。
     setHistoryCutoff((prev) => {
@@ -250,7 +248,6 @@ export default function ChatPage() {
       return next > prev ? next : prev;
     });
   }, [
-    hasSubmitted,
     historyCutoff,
     shouldRenderHistory,
     thread.isThreadLoading,
@@ -322,7 +319,6 @@ export default function ChatPage() {
       if (isNewThread && safeThreadId && !isThreadInitReady) {
         return;
       }
-      setHasSubmitted(true);
       if (safeThreadId && (isNewThread || showWelcomeStyle)) {
         router.replace(`/workspace/chats/${safeThreadId}?is_chatting=true`);
       }
@@ -343,22 +339,6 @@ export default function ChatPage() {
     await thread.stop();
   }, [thread]);
 
-  const resetNewSessionState = useCallback(() => {
-    setIsNewThread(true);
-    setHasSubmitted(false);
-    setHistoryCutoff(null);
-    setArtifacts([]);
-    deselectArtifact();
-    setArtifactsOpen(false);
-    setArtifactsFullscreen(false);
-  }, [
-    deselectArtifact,
-    setArtifacts,
-    setArtifactsFullscreen,
-    setArtifactsOpen,
-    setIsNewThread,
-  ]);
-
   return (
     <ThreadContext.Provider value={{ threadId, thread }}>
       <div
@@ -379,7 +359,7 @@ export default function ChatPage() {
               <header
                 className={cn(
                   "bg-background absolute top-0 right-0 left-0 z-30 mx-4 grid h-[58px] shrink-0 grid-cols-3 items-center border-b transition-all duration-300 ease-in-out",
-                  showWelcomeStyle && !hasSubmitted ? "hidden" : "",
+                  showWelcomeStyle ? "hidden" : "",
                 )}
               >
                 <div className="flex items-center justify-start overflow-hidden text-sm font-medium">
@@ -388,7 +368,14 @@ export default function ChatPage() {
                     variant="ghost"
                     className="px-[10px] py-[5px] text-sm font-medium text-ws-base-1 hover:text-ws-base-1/80"
                     disabled={isStreaming}
-                    onClick={() => setShowExitDialog(true)}
+                    onClick={() => {
+                      sendToParent({
+                        type: POST_MESSAGE_TYPES.IS_CHATTING,
+                        isChatting: false,
+                      });
+                      router.replace(`/workspace/chats/${threadId}?is_chatting=false`)
+                    }
+                    }
                   >
                     <svg
                       width="20"
@@ -444,6 +431,20 @@ export default function ChatPage() {
                       </Button>
                     }
                   /> */}
+                  <Tooltip content={t.common.resetThread}>
+                    <Button
+                      size="sm"
+                      variant="ghost"
+                      className="h-full px-[10px] py-[5px] text-sm font-medium text-ws-base-1 hover:text-ws-base-1"
+                      disabled={isStreaming}
+                      onClick={() => setShowExitDialog(true)}
+                    >
+                      <svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 18 18" fill="none">
+                        <path d="M2 4H6M16 4H12M6 4H12M6 4C6 2.89543 6.89543 2 8 2H10C11.1046 2 12 2.89543 12 4M4 6V14C4 15.1046 4.89543 16 6 16H12C13.1046 16 14 15.1046 14 14V6M7 8V13M11 8V13" stroke="#150033" stroke-linecap="round" />
+                      </svg>
+                      {t.common.resetThread}
+                    </Button>
+                  </Tooltip>
 
                   {artifacts?.length > 0 && !artifactsOpen && (
                     <Tooltip content={t.chatPage.viewArtifactsTooltip}>
@@ -456,7 +457,12 @@ export default function ChatPage() {
                           setSidebarOpen(false);
                         }}
                       >
-                        <FilesIcon />
+                        <svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 18 18" fill="none">
+                          <path d="M16 7V4C16 2.89543 15.1046 2 14 2H4C2.89543 2 2 2.89543 2 4V14C2 15.1046 2.89543 16 4 16H9" stroke="#150033" stroke-linecap="round" />
+                          <path d="M5 5H9M5 8H7" stroke="#150033" stroke-linecap="round" stroke-linejoin="round" />
+                          <circle cx="11.5" cy="10.5" r="3" stroke="#150033" />
+                          <path d="M15.5 14.5L14 13" stroke="#150033" stroke-linecap="round" stroke-linejoin="round" />
+                        </svg>
                         {t.common.artifacts}
                       </Button>
                     </Tooltip>
@@ -466,16 +472,14 @@ export default function ChatPage() {
               <main
                 className={cn(
                   "flex min-h-0 max-w-full grow flex-col",
-                  showWelcomeStyle && !hasSubmitted
+                  showWelcomeStyle ? "bg-ws-surface-base" : "bg-background",
-                    ? "bg-ws-surface-base"
-                    : "bg-background",
                 )}
               >
                 <div className="flex size-full justify-center">
                   <MessageList
                     className={cn(
                       "size-full",
-                      (!showWelcomeStyle || hasSubmitted) && "pt-[58px]",
+                      !showWelcomeStyle && "pt-[58px]",
                     )}
                     threadId={threadId}
                     thread={thread}
@@ -508,7 +512,7 @@ export default function ChatPage() {
             <div
               className={cn(
                 "h-full w-full transition-transform duration-300 ease-in-out",
-                showWelcomeStyle && !hasSubmitted ? "translate-x-0" : "",
+                showWelcomeStyle ? "translate-x-0" : "",
                 artifactPanelOpen ? "translate-x-0" : "translate-x-full",
               )}
             >
@@ -570,9 +574,7 @@ export default function ChatPage() {
           <div
             className={cn(
               "pointer-events-auto relative w-full max-w-[720px]",
-              showWelcomeStyle &&
+              showWelcomeStyle && "-translate-y-[calc(50vh-96px)]",
-                !hasSubmitted &&
-                "-translate-y-[calc(50vh-96px)]",
             )}
           >
             {!(showWelcomeStyle && thread.isThreadLoading) ? (
@@ -581,7 +583,6 @@ export default function ChatPage() {
                   className={cn("w-full rounded-[20px] bg-ws-surface-elevated")}
                   threadId={threadId}
                   showWelcomeStyle={showWelcomeStyle}
-                  hasSubmitted={hasSubmitted}
                   autoFocus={showWelcomeStyle}
                   status={
                     thread.error
@@ -593,9 +594,7 @@ export default function ChatPage() {
                   context={settings.context}
                   extraHeader={
                     <div className="flex flex-col gap-4">
-                      {showWelcomeStyle && !hasSubmitted && (
+                      {showWelcomeStyle && <Welcome mode={settings.context.mode} />}
-                        <Welcome mode={settings.context.mode} />
-                      )}
                     </div>
                   }
                   disabled={

frontend/src/components/workspace/input-box.tsx

@@ -219,7 +219,6 @@ export function InputBox({
   context,
   extraHeader,
   showWelcomeStyle,
-  hasSubmitted,
   initialValue,
   onContextChange,
   onSubmit,
@@ -238,7 +237,6 @@ export function InputBox({
   };
   extraHeader?: React.ReactNode;
   showWelcomeStyle: boolean;
-  hasSubmitted?: boolean;
   initialValue?: string;
   onContextChange?: (
     context: Omit<
@@ -294,14 +292,13 @@ export function InputBox({
   const [isInputToolsTourReady, setIsInputToolsTourReady] = useState(false);
   const { data: referenceFilesData } = useReferenceFiles(threadIdFromProps);
 
-  // isNewThread 时禁用收缩，始终保持展开（除非已提交消息）
+  // Welcome 态下禁用收缩，始终保持展开
-  const effectiveIsFocused =
+  const effectiveIsFocused = (showWelcomeStyle ?? false) || isFocused;
-    ((showWelcomeStyle ?? false) && !hasSubmitted) || isFocused;
   const shouldShowSuggestionList =
-    showWelcomeStyle && !hasSubmitted && searchParams.get("mode") !== "skill";
+    showWelcomeStyle && searchParams.get("mode") !== "skill";
 
   useEffect(() => {
-    if (!showWelcomeStyle || hasSubmitted) {
+    if (!showWelcomeStyle) {
       setIsInputToolsTourReady(false);
       return;
     }
@@ -318,14 +315,13 @@ export function InputBox({
     return () => window.cancelAnimationFrame(frameId);
   }, [
     showWelcomeStyle,
-    hasSubmitted,
     shouldShowSuggestionList,
     iframeSkill.isBootstrapping,
     iframeSkill.selectedSkills.length,
   ]);
 
   useEffect(() => {
-    if (!showWelcomeStyle || hasSubmitted || !isInputToolsTourReady) {
+    if (!showWelcomeStyle || !isInputToolsTourReady) {
       setIsInputToolsTourOpen(false);
       return;
     }
@@ -337,7 +333,7 @@ export function InputBox({
     if (!hasSeenTourForCurrentThread) {
       setIsInputToolsTourOpen(true);
     }
-  }, [showWelcomeStyle, hasSubmitted, isInputToolsTourReady, threadId]);
+  }, [showWelcomeStyle, isInputToolsTourReady, threadId]);
 
   const finishInputToolsTour = useCallback(() => {
     const seenState = parseInputToolsTourSeenState(
@@ -817,7 +813,6 @@ export function InputBox({
           "border-0 rounded-[20px] backdrop-blur-sm",
           "transition-[height] duration-300 ease-out shadow-none ",
           !showWelcomeStyle && "h-[200px] shadow-[0_0_20px_0_rgba(0,0,0,0.10)]",
-          hasSubmitted && "shadow-[0_0_20px_0_rgba(0,0,0,0.10)]!",
           effectiveIsFocused ? "h-[200px]" : "h-[80px]",
         )}
         disabled={isInputDisabled}
@@ -970,14 +965,14 @@ export function InputBox({
                 />
               </div>
             )}
-            {!showWelcomeStyle && (
+            {/* {!showWelcomeStyle && (
               <div className="shrink-0 h-full">
                 <ExitChattingButton
                   router={router}
                   threadId={threadIdFromProps}
                 />
               </div>
-            )}
+            )} */}
             <div ref={attachmentsButtonTourRef} className="shrink-0 h-full">
               <AddAttachmentsButton />
             </div>

frontend/src/core/i18n/locales/en-US.ts

@@ -53,6 +53,7 @@ export const enUS: Translations = {
     exportSuccess: "Conversation exported",
     removeAttachment: "Remove attachment",
     reference: "Reference",
+    resetThread: "Reset thread",
   },
 
   // Welcome

frontend/src/core/i18n/locales/types.ts

@@ -48,6 +48,7 @@ export interface Translations {
     exportSuccess: string;
     removeAttachment: string;
     reference: string;
+    resetThread: string;
   };
 
   // Welcome

frontend/src/core/i18n/locales/zh-CN.ts

@@ -55,6 +55,7 @@ export const zhCN: Translations = {
     exportSuccess: "对话已导出",
     removeAttachment: "移除附件",
     reference: "引用",
+    resetThread: "重置会话",
   },
 
   // Welcome