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/yt_data_extract/__init__.py

@@ -1,7 +1,7 @@
 from .common import (get, multi_get, deep_get, multi_deep_get,
     liberal_update, conservative_update, remove_redirect, normalize_url,
     extract_str, extract_formatted_text, extract_int, extract_approx_int,
-    extract_date, extract_item_info, extract_items, extract_response)
+    extract_date, extract_item_info, extract_items, extract_response, is_short)
 
 from .everything_else import (extract_channel_info, extract_search_info,
     extract_playlist_metadata, extract_playlist_info, extract_comments_info)

youtube/yt_data_extract/common.py

@@ -410,6 +410,51 @@ def extract_shorts_lockup_view_model_info(item, additional_info={}):
     return info
 
 
+def is_short(item_info):
+    """Check if a video item is a YouTube Short.
+
+    Shorts are identified by:
+    1. Duration < 60 seconds (typical Shorts length)
+    2. Having "Shorts" badge or type
+    3. Being extracted from shortsLockupViewModel or reelItemRenderer
+    """
+    if not item_info or item_info.get('error'):
+        return False
+
+    # Check renderer type
+    item_type = item_info.get('type', '')
+    if item_type == 'unsupported':
+        return False
+
+    # Check for "Shorts" badge
+    badges = item_info.get('badges', [])
+    if any('short' in str(badge).lower() for badge in badges):
+        return True
+
+    # Check duration (Shorts are typically < 60 seconds)
+    duration = item_info.get('duration')
+    if duration is not None:
+        # Duration can be string like "0:58" or "1:23:45" or int
+        if isinstance(duration, str):
+            # Parse duration string to seconds
+            parts = duration.split(':')
+            try:
+                if len(parts) == 2:  # MM:SS
+                    duration_seconds = int(parts[0]) * 60 + int(parts[1])
+                elif len(parts) == 3:  # HH:MM:SS
+                    duration_seconds = int(parts[0]) * 3600 + int(parts[1]) * 60 + int(parts[2])
+                else:
+                    duration_seconds = int(duration)
+                if duration_seconds < 60:
+                    return True
+            except (ValueError, IndexError):
+                pass
+        elif isinstance(duration, (int, float)) and duration < 60:
+            return True
+
+    return False
+
+
 def extract_item_info(item, additional_info={}):
     if not item:
         return {'error': 'No item given'}