feat(md-deck): Add fallback copy dialog for clipboard failure

src/components/md-deck/hooks/deckStore.ts

@@ -145,7 +145,7 @@ export interface DeckActions {
   clearError: () => void;
 
   generateCode: (backLayersStr?: string) => string;
-  copyCode: (backLayersStr?: string) => Promise<void>;
+  copyCode: (fallback?: (code: string) => void) => Promise<void>;
 
   setExporting: (exporting: boolean) => void;
   exportDeck: () => void;
@@ -514,14 +514,18 @@ export function createDeckStore(initialSrc: string = ""): DeckStore {
     return parts.join("");
   };
 
-  const copyCode = async (backLayersStr?: string) => {
-    const code = generateCode(backLayersStr);
+  const copyCode = async (fallback?: (code: string) => void) => {
+    const code = generateCode();
     try {
       await navigator.clipboard.writeText(code);
       alert("已复制到剪贴板！");
     } catch (err) {
       console.error("复制失败:", err);
-      alert("复制失败，请手动复制");
+      if (fallback) {
+        fallback(code);
+      } else {
+        alert("复制失败，请手动复制");
+      }
     }
   };