feat(video): add autoplay and dynamic video loading

- Add autoplay attribute to video player
- Implement dynamic calculation of needed regular videos based on window height
- Update video comments with Japanese content and remove default avatars

video.html

@@ -169,7 +169,7 @@
                 <div class="video-main-section">
                     <!-- Video Player -->
                     <div class="video-player">
-                        <video src="src/video.mp4" controls></video>
+                        <video src="src/video.mp4" controls autoplay></video>
                     </div>
 
                     <!-- Video Info -->