feat: 优化多个页面功能和界面

主要更新：
1. CoursesVideoPlayer组件：修复了白底logo容器边框样式
2. 专家支持中心：
   - 导入文旅产业问答数据
   - 清空今天板块对话记录
   - 禁用新建对话按钮，添加hover提示"非学员无权限"
3. 就业管家知识树：整个页面替换为iframe嵌入网页
4. 项目库：为四川大熊猫扇子项目添加3张效果图
5. 简历面试模拟：为活动执行和活动策划师岗位添加删除线修改版本

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/components/CoursesVideoPlayer/index.css

@@ -16,7 +16,7 @@
     padding: 16px;
     border-radius: 16px;
     background-color: #fff;
-    border: 1px solid #fff;
+    border: 1px solid #e5e6eb;
 
     .courses-video-player-header {
       width: 100%;
@@ -63,7 +63,7 @@
     margin-top: 20px;
     width: 100%;
     height: 234px;
-    border: 2px solid #fff;
+    border: 1px solid #e5e6eb;
     border-radius: 16px;
     box-sizing: border-box;
     padding: 16px;

src/components/CoursesVideoPlayer/index.jsx

@@ -1,5 +1,6 @@
 import { Avatar, Tooltip } from "@arco-design/web-react";
 import Locked from "@/components/Locked";
+import logoImg from "@/assets/images/Sidebar/logo.png";
 import "./index.css";
 
 export default ({ className = "", isLock = false, selectedCourse, teacherData, unitPosters, isPublicCourse = false, backgroundImage }) => {
@@ -146,17 +147,30 @@ export default ({ className = "", isLock = false, selectedCourse, teacherData, u
                     </div>
                   </div>
               ) : (
-                /* 未选中课程时显示黑屏 */
+                /* 未选中课程时显示白底和logo */
                 <div style={{ 
                   width: '100%', 
                   height: '100%', 
-                  backgroundColor: '#000',
+                  backgroundColor: '#fff',
+                  border: '1px solid #e5e6eb',
+                  borderRadius: '8px',
                   display: 'flex',
+                  flexDirection: 'column',
                   alignItems: 'center',
-                  justifyContent: 'center'
+                  justifyContent: 'center',
+                  gap: '24px'
                 }}>
+                  <img 
+                    src={logoImg} 
+                    alt="logo" 
+                    style={{ 
+                      width: '120px', 
+                      height: 'auto',
+                      opacity: 0.8
+                    }}
+                  />
                   <span style={{
-                    color: '#666',
+                    color: '#86909c',
                     fontSize: '16px'
                   }}>
                     请选择课程开始观看