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

.gitignore

@@ -1,5 +1,128 @@
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+*.py[cod]
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+
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+build/
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+dist/
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+wheels/
+pip-wheel-metadata/
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+.cache
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+ipython_config.py
+
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+# PEP 582
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+celerybeat-schedule
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+*.sage.py
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+.env
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@@ -11,5 +134,17 @@ get-pip.py
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+.vscode/
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+*.swp
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+*.orig