feat(ui/agents): add ToolCallCard

Collapsible card for assistant tool invocations from tool_call events.
Cursor Cloud Agents-style: collapsed shows tool + preview; expanded
shows full input (and result, when present).

ui/litellm-dashboard/src/app/(dashboard)/agents/components/three-pane/tool-call-card.tsx

@@ -0,0 +1,63 @@
+"use client";
+
+/**
+ * ToolCallCard — collapsible card rendering an assistant tool invocation.
+ *
+ * Used for `tool_call` events. The Cursor Cloud Agents UI shows these
+ * collapsed by default with the tool name + a one-line preview, expanded
+ * on click to show the full input.
+ */
+import { useState } from "react";
+import { Card, Tag, Typography, Button } from "antd";
+import { CaretRightOutlined, CaretDownOutlined } from "@ant-design/icons";
+
+const { Text, Paragraph } = Typography;
+
+interface ToolCallCardProps {
+  tool: string;
+  input: string;
+  result?: string;
+}
+
+export default function ToolCallCard({ tool, input, result }: ToolCallCardProps) {
+  const [expanded, setExpanded] = useState(false);
+  return (
+    <Card size="small" className="!mb-3" data-testid="tool-call-card" bodyStyle={{ padding: 8 }}>
+      <div className="flex items-center gap-2">
+        <Button
+          size="small"
+          type="text"
+          icon={expanded ? <CaretDownOutlined /> : <CaretRightOutlined />}
+          onClick={() => setExpanded((v) => !v)}
+          data-testid="tool-call-toggle"
+        />
+        <Tag color="cyan" className="!m-0">
+          {tool}
+        </Tag>
+        {!expanded && (
+          <Text type="secondary" className="!truncate !text-xs">
+            {input.slice(0, 80)}
+          </Text>
+        )}
+      </div>
+      {expanded && (
+        <div className="mt-2 space-y-2">
+          <div>
+            <Text strong className="!text-xs">
+              input
+            </Text>
+            <Paragraph className="!mb-0 whitespace-pre-wrap !text-xs !font-mono">{input}</Paragraph>
+          </div>
+          {result && (
+            <div>
+              <Text strong className="!text-xs">
+                result
+              </Text>
+              <Paragraph className="!mb-0 whitespace-pre-wrap !text-xs !font-mono">{result}</Paragraph>
+            </div>
+          )}
+        </div>
+      )}
+    </Card>
+  );
+}