fix: 修改公共课直播间显示逻辑，将今日课程改为即将开始状态

- 公共课直播间恢复使用视频播放器
- 将今日课程状态从直播中改为即将开始
- 更新generateCourseLiveList.js逻辑

src/components/CoursesVideoPlayer/index.jsx

@@ -81,15 +81,7 @@ export default ({ className = "", isLock = false, selectedCourse, teacherData, u
               <span onClick={() => handleClickBtn(2)}>下一集 &gt;</span>
             </div>
             <div className="courses-video-player-video">
-              {selectedCourse?.current ? (
-                <video src="/live.mp4" autoPlay controls></video>
-              ) : (
-                <img 
-                  src={unitPosters?.[unitName] || unitPosters?.["岗位体系认知"]} 
-                  alt={unitName}
-                  style={{ width: '100%', height: '100%', objectFit: 'cover' }}
-                />
-              )}
+              <video src="/live.mp4" autoPlay controls></video>
             </div>
           </>
         )}