fix: 会商沙箱预览头仅在可提交的 Markdown 产物显示提交按钮

frontend-web/src/roundtable-planning/components/Step2SandboxLayout.tsx

@@ -144,6 +144,25 @@ export function Step2SandboxLayout({
   }, [artifacts, isStreaming, seatMessages]);
 
   const previewThreadId = activeThreadId ?? "";
+  const selectedArtifactTarget = useMemo(() => {
+    const target = {
+      threadId: previewThreadId,
+      path: selectedArtifact ?? "",
+      content: selectedArtifactContent,
+    };
+    return taskArtifactSubmission?.targetFor(target) ?? target;
+  }, [
+    previewThreadId,
+    selectedArtifact,
+    selectedArtifactContent,
+    taskArtifactSubmission,
+  ]);
+  // 8BF 等接入任务过程产物提交的页面，用提交按钮替换文件类型；其余普通/任务深链
+  // 会商仍保留原有文件类型徽标。非 Markdown 产物本身不能提交，也应显示类型。
+  const showTaskArtifactSubmit = Boolean(
+    taskArtifactSubmission?.enabled
+      && taskArtifactSubmission.isMarkdown(selectedArtifactTarget),
+  );
 
   const artifactPanelBody = (
     <div
@@ -162,18 +181,14 @@ export function Step2SandboxLayout({
           onClose={artifactsFill && onArtifactsClose ? handleArtifactsClose : undefined}
           // 会商「消息列表沙箱」按需求不脱敏产物内容（用户要拿原始文件）。
           disableDesensitize
-          headerLeadingActionBare
+          headerLeadingAction={showTaskArtifactSubmit ? (
-          headerLeadingAction={(
             <TaskArtifactSubmitButton
               compact
               controller={taskArtifactSubmission}
-              target={taskArtifactSubmission?.targetFor({
+              target={selectedArtifactTarget}
-                threadId: previewThreadId,
-                path: selectedArtifact,
-                content: selectedArtifactContent,
-              }) ?? { threadId: previewThreadId, path: selectedArtifact }}
             />
-          )}
+          ) : undefined}
+          headerLeadingActionBare={showTaskArtifactSubmit}
         />
       ) : (
         <div className="relative flex size-full justify-center">