Release v0.4.0 - HD Thumbnails, YouTube 2024+ Support, and yt-dlp Integration

Major Features:
- HD video thumbnails (hq720.jpg) with automatic fallback to lower qualities
- HD channel avatars (240x240 instead of 88x88)
- YouTube 2024+ lockupViewModel support for channel playlists
- youtubei/v1/browse API integration for channel playlist tabs
- yt-dlp integration for multi-language audio and subtitles

Bug Fixes:
- Fixed undefined `abort` import in playlist.py
- Fixed undefined functions in proto.py (encode_varint, bytes_to_hex, succinct_encode)
- Fixed missing `traceback` import in proto_debug.py
- Fixed blurry playlist thumbnails using default.jpg instead of HD versions
- Fixed channel playlists page using deprecated pbj=1 format

Improvements:
- Automatic thumbnail fallback system (hq720 → sddefault → hqdefault → mqdefault → default)
- JavaScript thumbnail_fallback() handler for 404 errors
- Better thumbnail quality across all pages (watch, channel, playlist, subscriptions)
- Consistent HD avatar display for all channel items
- Settings system automatically adds new settings without breaking user config

Files Modified:
- youtube/watch.py - HD thumbnails for related videos and playlist items
- youtube/channel.py - HD thumbnails for channel playlists, youtubei API integration
- youtube/playlist.py - HD thumbnails, fixed abort import
- youtube/util.py - HD thumbnail URLs, avatar HD upgrade, prefix_url improvements
- youtube/comments.py - HD video thumbnail
- youtube/subscriptions.py - HD thumbnails, fixed abort import
- youtube/yt_data_extract/common.py - lockupViewModel support, extract_lockup_view_model_info()
- youtube/yt_data_extract/everything_else.py - HD playlist thumbnails
- youtube/proto.py - Fixed undefined function references
- youtube/proto_debug.py - Added traceback import
- youtube/static/js/common.js - thumbnail_fallback() handler
- youtube/templates/*.html - Added onerror handlers for thumbnail fallback
- youtube/version.py - Bump to v0.4.0

Technical Details:
- All thumbnail URLs now use hq720.jpg (1280x720) when available
- Fallback handled client-side via JavaScript onerror handler
- Server-side avatar upgrade via regex in util.prefix_url()
- lockupViewModel parser extracts contentType, metadata, and first_video_id
- Channel playlist tabs now use youtubei/v1/browse instead of deprecated pbj=1
- Settings version system ensures backward compatibility

server.py

@@ -279,6 +279,16 @@ if __name__ == '__main__':
 
     print('Starting httpserver at http://%s:%s/' %
           (ip_server, settings.port_number))
+
+    # Show privacy-focused tips
+    print('')
+    print('Privacy & Rate Limiting Tips:')
+    print('  - Enable Tor routing in /settings for anonymity and better rate limits')
+    print('  - The system auto-retries with exponential backoff (max 5 retries)')
+    print('  - Wait a few minutes if you hit rate limits (429)')
+    print('  - For maximum privacy: Use Tor + No cookies')
+    print('')
+
     server.serve_forever()
 
 # for uwsgi, gunicorn, etc.