feat: 添加作品购买人列表功能

frontend/admin/src/api/postService.js

@@ -26,4 +26,9 @@ export const postService = {
     sendTo(id, userId) {
         return httpClient.post(`/posts/${id}/send-to/${userId}`);
     },
-}
+    getBuyers(id, { page = 1, limit = 10 } = {}) {
+        return httpClient.get(`/posts/${id}/buyers`, {
+            params: { page, limit }
+        });
+    },
+}