fix(frontend): use native confirm for share/direct-link deletion

frontend/app.js

@@ -2960,7 +2960,7 @@ handleDragLeave(e) {
     },
 
     async deleteDirectLink(id) {
-      if (!confirm('确定要删除这个直链吗？')) return;
+      if (!window.confirm('确定要删除这个直链吗？')) return;
 
       try {
         const response = await axios.delete(`${this.apiBase}/api/direct-link/${id}`);
@@ -2995,7 +2995,7 @@ handleDragLeave(e) {
     },
 
     async deleteShare(id) {
-      if (!confirm('确定要删除这个分享吗？')) return;
+      if (!window.confirm('确定要删除这个分享吗？')) return;
 
       try {
         const response = await axios.delete(`${this.apiBase}/api/share/${id}`);