chore: 更新应用版本至2.0.51并调整依赖配置

- 将应用版本从2.0.49提升至2.0.51
- 修改edu-core依赖为本地文件引用
- 更新多个页面的下拉刷新和底部加载逻辑
- 优化VIP权限描述，明确不包含论坛权益
- 调整部分页面样式以提升用户体验

package.json

@@ -7,7 +7,7 @@
 	"dependencies": {
 		"animate.css": "^4.1.1",
 		"e-peanut": "file:",
-		"edu-core": "git+https://git.nuttyreading.com/chenghuan/edu-core.git#v1.0.13",
+		"edu-core": "file:../edu-core",
 		"element-plus": "^2.9.6",
 		"epubjs": "^0.3.93",
 		"jquery": "^2.2.4",