Archive finished subagents across the whole track (#3368)

* feat(app): archive finished subagents together

Make the track action clean up finished managed and provider-owned children as one operation while preserving running work. Managed archives remain sequential and provider-owned dismissal stays client-local.

* test(app): clarify subagent archive assertions

packages/app/src/panels/agent-panel.tsx

@@ -88,7 +88,7 @@ import { useWorkspaceLayoutStore } from "@/stores/workspace-layout-store";
 import { buildWorkspaceTabPersistenceKey } from "@/workspace-tabs/model";
 import type { Theme } from "@/styles/theme";
 import {
-  useHideFinishedProviderSubagents,
+  useArchiveFinishedSubagents,
   useArchiveSubagent,
   useDetachSubagent,
   useSubagentsForParent,
@@ -1532,9 +1532,10 @@ function ActiveAgentComposer({
   );
   const handleArchiveSubagent = useArchiveSubagent({ serverId });
   const handleDetachSubagent = useDetachSubagent({ serverId });
-  const handleHideFinishedProviderSubagents = useHideFinishedProviderSubagents({
+  const archiveFinishedSubagents = useArchiveFinishedSubagents({
     serverId,
     parentAgentId: agentId,
+    rows: subagentRows,
   });
   const workspaceAttachmentScopeKey = useWorkspaceAttachmentScopeKey({
     serverId,
@@ -1628,7 +1629,8 @@ function ActiveAgentComposer({
         onOpenSubagent={handleOpenSubagent}
         onOpenProviderSubagent={handleOpenProviderSubagent}
         onArchiveSubagent={handleArchiveSubagent}
-        onArchiveFinished={handleHideFinishedProviderSubagents}
+        onArchiveFinished={archiveFinishedSubagents.archiveFinished}
+        archiveFinishedStatus={archiveFinishedSubagents.status}
         onDetachSubagent={canDetachSubagents ? handleDetachSubagent : undefined}
       />
       <Composer