feat(pipeline-progress): expandable agent rows with output and error details

Click an agent row to toggle its expanded view; expanded rows surface
outputSummary and any error text. Adds chevron icons, hover affordance,
and a shrink-0 guard on status icons so they keep their size in flex layouts.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

components/pipeline-progress.tsx

@@ -1,6 +1,7 @@
 "use client";
 
-import { CheckCircle2, Circle, Loader2, XCircle } from "lucide-react";
+import { useState } from "react";
+import { CheckCircle2, ChevronDown, ChevronRight, Circle, Loader2, XCircle } from "lucide-react";
 import type { AgentStatus } from "@/hooks/use-pipeline-progress";
 
 const AGENT_LABELS: Record<string, string> = {
@@ -23,44 +24,82 @@ function formatDuration(ms?: number) {
 function StatusIcon({ status }: { status: AgentStatus["status"] }) {
   switch (status) {
     case "completed":
-      return <CheckCircle2 className="h-5 w-5 text-green-500" />;
+      return <CheckCircle2 className="h-5 w-5 text-green-500 shrink-0" />;
     case "running":
-      return <Loader2 className="h-5 w-5 animate-spin text-blue-500" />;
+      return <Loader2 className="h-5 w-5 animate-spin text-blue-500 shrink-0" />;
     case "failed":
-      return <XCircle className="h-5 w-5 text-red-500" />;
+      return <XCircle className="h-5 w-5 text-red-500 shrink-0" />;
     default:
-      return <Circle className="h-5 w-5 text-muted-foreground" />;
+      return <Circle className="h-5 w-5 text-muted-foreground shrink-0" />;
   }
 }
 
+function AgentRow({ agent }: { agent: AgentStatus }) {
+  const [expanded, setExpanded] = useState(false);
+  const hasDetails = agent.outputSummary || agent.error;
+
+  return (
+    <div
+      className={`rounded-lg border transition-colors ${hasDetails ? "cursor-pointer hover:bg-muted/50" : ""}`}
+      onClick={() => hasDetails && setExpanded(!expanded)}
+    >
+      <div className="flex items-center gap-3 p-3">
+        <StatusIcon status={agent.status} />
+        <div className="flex-1 min-w-0">
+          <div className="font-medium">
+            {AGENT_LABELS[agent.agentName] || agent.agentName}
+          </div>
+          {!expanded && agent.outputSummary && (
+            <p className="text-sm text-muted-foreground line-clamp-1">
+              {agent.outputSummary}
+            </p>
+          )}
+          {!expanded && agent.error && (
+            <p className="text-sm text-red-500 line-clamp-1">{agent.error}</p>
+          )}
+        </div>
+        {agent.durationMs && (
+          <span className="text-sm text-muted-foreground shrink-0">
+            {formatDuration(agent.durationMs)}
+          </span>
+        )}
+        {hasDetails && (
+          expanded
+            ? <ChevronDown className="h-4 w-4 text-muted-foreground shrink-0" />
+            : <ChevronRight className="h-4 w-4 text-muted-foreground shrink-0" />
+        )}
+      </div>
+      {expanded && (
+        <div className="border-t px-3 py-3 space-y-2">
+          {agent.error && (
+            <div>
+              <div className="text-xs font-medium text-red-500 uppercase mb-1">Error</div>
+              <p className="text-sm text-red-500 whitespace-pre-wrap">{agent.error}</p>
+            </div>
+          )}
+          {agent.outputSummary && (
+            <div>
+              <div className="text-xs font-medium text-muted-foreground uppercase mb-1">Output</div>
+              <p className="text-sm text-muted-foreground whitespace-pre-wrap">{agent.outputSummary}</p>
+            </div>
+          )}
+          {agent.durationMs && (
+            <div>
+              <div className="text-xs font-medium text-muted-foreground uppercase mb-1">Duration</div>
+              <p className="text-sm text-muted-foreground">{formatDuration(agent.durationMs)}</p>
+            </div>
+          )}
+        </div>
+      )}
+    </div>
+  );
+}
+
 export function PipelineProgress({ agents }: { agents: AgentStatus[] }) {
   return (
     <div className="space-y-3">
       {agents.map((agent) => (
-        <div
+        <AgentRow key={agent.agentName} agent={agent} />
-          key={agent.agentName}
-          className="flex items-center gap-3 rounded-lg border p-3"
-        >
-          <StatusIcon status={agent.status} />
-          <div className="flex-1">
-            <div className="font-medium">
-              {AGENT_LABELS[agent.agentName] || agent.agentName}
-            </div>
-            {agent.outputSummary && (
-              <p className="text-sm text-muted-foreground line-clamp-1">
-                {agent.outputSummary}
-              </p>
-            )}
-            {agent.error && (
-              <p className="text-sm text-red-500 line-clamp-1">{agent.error}</p>
-            )}
-          </div>
-          {agent.durationMs && (
-            <span className="text-sm text-muted-foreground">
-              {formatDuration(agent.durationMs)}
-            </span>
-          )}
-        </div>
       ))}
     </div>
   );