feat: add thumbnail preview, audio-only detection, /download command, tests, and bugfixes

- Add thumbnail preview with metadata (title, uploader, duration) before download
- Auto-detect audio-only sites (Spotify, SoundCloud, etc.) and skip type selection
- Add /download command for feature parity with UI button
- Fix yt-dlp defer bug: StatusFailed was overwritten to StatusCompleted
- Fix handleURLInput using editText with msgID=0 (now uses sendWithKB)
- Fix filename detection: use job ID prefix for reliable file finding
- Fix double answerCb between handleBackStep and handleDownloadPrompt
- Fix runDownload unused msgID parameter
- Fix context for download goroutine (use context.Background)
- Remove unused startWebhook h parameter
- Remove dead buildToggleKeyboard function
- Add formatBytes, formatDuration, formatLabelForDisplay tests
- Add IsAudioOnlyContent, MediaType.String tests
- Add repo integration tests (users, preferences, quotas, history, delete)
- Add cmd/bot tests (parseAllowedUsers, env helpers)
- Add edge case tests for progress parser
- Add zero/negative safety guard in formatDuration
- Add .gitea, TODO.md, opencode.json to gitignore

README.md

@@ -1,14 +1,16 @@
 # uptodownbot
 
-Telegram bot for downloading media from supported sites using yt-dlp.
+Telegram bot for downloading media from any site yt-dlp supports.
 
 ## Features
 
-- Download audio, video, or combined audio+video from any site yt-dlp supports
+- Download audio, video, or combined audio+video from YouTube, Spotify, SoundCloud, Vimeo, and hundreds more
+- Thumbnail preview with metadata (title, uploader, duration) before download
+- Audio-only sites (Spotify, SoundCloud, YouTube Music, etc.) auto-detect and skip to audio quality selection
 - Multi-step format selection: media type, quality, language, container
-- Playlist support with paginated entry selection (10 per page)
-- Download progress updates (every 5%)
-- Cancel downloads at any time
+- Playlist support with paginated entry selection (10 per page, select all, confirm with count)
+- Download progress updates (every 5% with speed and ETA)
+- Cancel downloads at any time (terminates yt-dlp process)
 - Per-user quota system (daily, weekly, monthly)
 - User preferences (default quality, container, language)
 - Download history
@@ -21,11 +23,12 @@ Telegram bot for downloading media from supported sites using yt-dlp.
 ## Commands
 
 - `/start` - Show main menu
+- `/download` - Prompt for a download URL
 - `/settings` - Open settings
 - `/help` - Show help text
 - `/history` - View download history
 
-Just send a URL to start downloading.
+You can also send a URL directly to start downloading immediately.
 
 ## Configuration