feat: add Spanish README and improve channel/playlist handling

* Add complete Spanish translation (README.es.md)
* Restructure English README for clarity and conciseness
* Filter out YouTube Shorts from channel video listings (sort=4)
* Add fallback for video count using playlist metadata when API returns zero
* Add get_playlist_metadata() to fetch metadata without full video list
* Add is_short() utility to detect YouTube Shorts by duration, badges, and type
* Export is_short from yt_data_extract for use across modules

youtube/channel.py

@@ -475,6 +475,27 @@ def get_channel_page_general_url(base_url, tab, request, channel_id=None):
             pl_info = yt_data_extract.extract_playlist_info(pl_json)
             number_of_videos = tasks[2].value
 
+            # Filter out shorts locally if sort=4 (YouTube may not honor API filter)
+            if sort == '4' and pl_info.get('items'):
+                pl_info['items'] = [
+                    item for item in pl_info['items']
+                    if not yt_data_extract.is_short(item)
+                ]
+
+            # If channel API count is missing/zero, get from playlist metadata
+            if not number_of_videos or number_of_videos == 0:
+                try:
+                    metadata_json = playlist.get_playlist_metadata(
+                        'UU' + channel_id[2:],
+                        report_text='Retrieved playlist metadata'
+                    )
+                    metadata_info = yt_data_extract.extract_playlist_info(metadata_json)
+                    metadata_video_count = metadata_info['metadata'].get('video_count')
+                    if metadata_video_count:
+                        number_of_videos = metadata_video_count
+                except Exception:
+                    pass
+
         info = pl_info
         info['channel_id'] = channel_id
         info['current_tab'] = 'videos'