Preserve QWord strikethrough formatting

src/features/qword/QWord.tsx

@@ -14,6 +14,7 @@ import {
   PaintBucket,
   Pilcrow,
   Save,
+  Strikethrough,
   Type,
   Underline
 } from "lucide-react";
@@ -268,6 +269,9 @@ export function QWord({ document, onChange }: QWordProps) {
             <button type="button" onClick={() => runCommand("underline")} title="Подчеркнутый">
               <Underline size={16} />
             </button>
+            <button type="button" onClick={() => runCommand("strikeThrough")} title="Зачеркнутый" aria-label="Зачеркнутый">
+              <Strikethrough size={16} />
+            </button>
             <button type="button" onClick={() => runCommand("insertUnorderedList")} title="Маркированный список">
               <List size={16} />
             </button>