feat: add workspace management editor

frontend/src/shell/ModelActivityPanel.tsx

@@ -1,5 +1,5 @@
 import { useLayoutEffect, useRef } from "react";
-import { X } from "lucide-react";
+import { Settings2, X } from "lucide-react";
 import ReactMarkdown from "react-markdown";
 import remarkGfm from "remark-gfm";
 import type { ActivityEntry, ActivityKind } from "../api/types";
@@ -61,9 +61,11 @@ function ActivityRow({ entry }: { entry: ActivityEntry }) {
 export function ModelActivityPanel({
   desktopSplit = false,
   onClose,
+  onOpenWorkspaceManager,
 }: {
   desktopSplit?: boolean;
   onClose: () => void;
+  onOpenWorkspaceManager?: () => void;
 }) {
   const activityLog = useSessionStore((s) => s.activityLog);
   const visibleActivity = activityLog.filter(isVisibleModelActivity);
@@ -82,11 +84,16 @@ export function ModelActivityPanel({
       ? "static z-auto flex min-w-0 w-[var(--activity-panel-width)] shrink-0 flex-col border-r-0 bg-sidebar"
       : "fixed inset-y-0 left-0 z-30 flex min-w-0 w-[min(90vw,24rem)] shrink-0 flex-col border-r border-border bg-sidebar"
     }>
-      <div className="flex items-center justify-between border-b border-border/60 px-3 py-2">
+      <div className="flex items-center justify-between gap-2 border-b border-border/60 px-3 py-2">
         <h2 className="font-heading text-sm font-semibold text-foreground">Model activity</h2>
-        <Button size="icon-sm" variant="ghost" aria-label="Close model activity" onClick={onClose}>
-          <X className="size-4" />
-        </Button>
+        <div className="flex items-center gap-1">
+          <Button size="sm" variant="ghost" aria-label="Workspace management" onClick={onOpenWorkspaceManager}>
+            <Settings2 className="size-3.5" />Workspace management
+          </Button>
+          <Button size="icon-sm" variant="ghost" aria-label="Close model activity" onClick={onClose}>
+            <X className="size-4" />
+          </Button>
+        </div>
       </div>
       <div
         ref={scrollRef}