feat: add undo/redo buttons to TopBar with tooltips

src/components/layout/TopBar.tsx

@@ -1,5 +1,5 @@
 import { useState, useRef, useEffect, useCallback } from "react";
-import { ArrowLeft, Settings, Search } from "lucide-react";
+import { ArrowLeft, Settings, Search, Undo2, Redo2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import {
   Tooltip,
@@ -124,6 +124,40 @@ export function TopBar() {
 
       {/* Right section */}
       <div className="flex items-center gap-1">
+        {isBoardView && (
+          <>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="ghost"
+                  size="icon-sm"
+                  className="text-pylon-text-secondary hover:text-pylon-text"
+                  onClick={() => useBoardStore.temporal.getState().undo()}
+                >
+                  <Undo2 className="size-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>
+                Undo <kbd className="ml-1 font-mono text-[10px] opacity-60">Ctrl+Z</kbd>
+              </TooltipContent>
+            </Tooltip>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="ghost"
+                  size="icon-sm"
+                  className="text-pylon-text-secondary hover:text-pylon-text"
+                  onClick={() => useBoardStore.temporal.getState().redo()}
+                >
+                  <Redo2 className="size-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>
+                Redo <kbd className="ml-1 font-mono text-[10px] opacity-60">Ctrl+Shift+Z</kbd>
+              </TooltipContent>
+            </Tooltip>
+          </>
+        )}
         {savingStatus && (
           <span className="mr-2 font-mono text-xs text-pylon-text-secondary">
             {savingStatus}