新增 undo 功能

client/src/pages/eq/components/FreqChart.tsx

@@ -7,6 +7,7 @@ import {
 } from "@/lib/peqAudio";
 import type { PeqEqUi } from "../constants";
 import { eqInterp } from "../utils";
+import { PeqUndoButton } from "./PeqUndoButton";
 
 /* ── Legend indicator ── */
 function LegendCurveIndicator({
@@ -37,6 +38,8 @@ export function FreqChart({
   abMode,
   onAbToggle,
   onCopyAndSwitchTo,
+  canUndo,
+  onUndo,
   onApplyB,
   onSaveB,
   onBandDrag,
@@ -52,6 +55,8 @@ export function FreqChart({
   abMode: "A" | "B";
   onAbToggle: (m: "A" | "B") => void;
   onCopyAndSwitchTo: (to: "A" | "B") => void;
+  canUndo: boolean;
+  onUndo: () => void;
   onApplyB: () => void;
   onSaveB: () => void;
   onBandDrag: (idx: number, patch: Partial<{ freq: number; gain: number }>) => void;
@@ -295,6 +300,11 @@ export function FreqChart({
           }}>
           {copyButtonText}
         </button>
+        <PeqUndoButton
+          disabled={!canUndo}
+          label={eqUi.undo ?? "Undo"}
+          onClick={onUndo}
+        />
         </div>
         <div className="ml-auto flex shrink-0 items-center gap-2">
         <button