fix(chat): collapse long activity commands

src/components/chat/AgentActivityTimeline.tsx

@@ -3,6 +3,7 @@
 import React, { useEffect, useMemo, useState } from "react";
 import {
   Box,
+  Button,
   Collapse,
   IconButton,
   LinearProgress,
@@ -89,6 +90,11 @@ const ActionStatusIcon = ({ status }: { status: AgentActivityAction["status"] })
 
 const ActionRow = ({ action, now }: { action: AgentActivityAction; now: number }) => {
   const elapsed = getElapsedMs(action, now);
+  const [targetExpanded, setTargetExpanded] = useState(false);
+  const targetId = React.useId();
+  const target = action.target ?? "";
+  const targetPreview = target.split(/\r?\n/u).slice(0, 3).join("\n").slice(0, 240);
+  const hasLongTarget = targetPreview.length < target.length;
   return (
     <Stack
       direction="row"
@@ -111,19 +117,45 @@ const ActionRow = ({ action, now }: { action: AgentActivityAction; now: number }
           </Typography>
         </Stack>
         {action.target ? (
-          <Typography
-            variant="caption"
-            color="text.secondary"
-            sx={{
-              display: "block",
-              mt: 0.2,
-              fontFamily: "monospace",
-              wordBreak: "break-word",
-              whiteSpace: "pre-wrap",
-            }}
-          >
-            {action.target}
-          </Typography>
+          <Box sx={{ mt: 0.2 }}>
+            <Typography
+              id={targetId}
+              variant="caption"
+              color="text.secondary"
+              sx={{
+                display: !targetExpanded && hasLongTarget ? "-webkit-box" : "block",
+                fontFamily: "monospace",
+                overflow: !targetExpanded && hasLongTarget ? "hidden" : "visible",
+                overflowWrap: "anywhere",
+                whiteSpace: "pre-wrap",
+                ...(!targetExpanded && hasLongTarget
+                  ? { WebkitBoxOrient: "vertical", WebkitLineClamp: 3 }
+                  : {}),
+              }}
+            >
+              {targetExpanded ? target : targetPreview}
+            </Typography>
+            {hasLongTarget ? (
+              <Button
+                size="small"
+                aria-controls={targetId}
+                aria-expanded={targetExpanded}
+                onClick={() => setTargetExpanded((current) => !current)}
+                sx={{
+                  mt: 0.2,
+                  p: 0,
+                  minWidth: 0,
+                  color: activityAccent,
+                  fontSize: "0.75rem",
+                  fontWeight: 650,
+                  lineHeight: 1.5,
+                  textTransform: "none",
+                }}
+              >
+                {targetExpanded ? "收起内容" : "展开完整内容"}
+              </Button>
+            ) : null}
+          </Box>
         ) : null}
         {action.error ? (
           <Typography