新增 undo 功能

client/src/pages/EQPage.tsx

@@ -87,7 +87,6 @@ import { ShareDialog } from "./eq/components/ShareDialog";
 import { BrandDrawer } from "./eq/components/BrandDrawer";
 import { PeqOverwriteConfirmDialog } from "./eq/components/PeqOverwriteConfirmDialog";
 import { PeqPresetManageDialog } from "./eq/components/PeqPresetManageDialog";
-import { PeqUndoButton } from "./eq/components/PeqUndoButton";
 import { useRawCurve } from "./eq/hooks/useRawCurve";
 import {
   usePeqUndoHistory,
@@ -1795,11 +1794,6 @@ export default function EQPage() {
               )}
             </div>
             <div className="flex shrink-0 items-center gap-2">
-              <PeqUndoButton
-                disabled={!canUndo}
-                label={eqUi.undo ?? "Undo"}
-                onClick={handleUndo}
-              />
               <button
                 className="w-9 h-9 rounded-full flex items-center justify-center text-white/60 active:text-white transition-colors"
                 style={{
@@ -1844,6 +1838,8 @@ export default function EQPage() {
             abMode={abMode}
             onAbToggle={handleAbToggle}
             onCopyAndSwitchTo={handleCopyAndSwitchTo}
+            canUndo={canUndo}
+            onUndo={handleUndo}
             onApplyB={() => void handleApplyB()}
             onSaveB={openSaveBDialog}
             onBandDrag={(idx, patch) =>