feat: add auto-select from preferences and type picker

- Add MediaTypeAsk (0) as the default, mapping old video_audio to Ask
- Show Video/Audio/Ask type picker when no default media type is set
- Auto-select matching format and skip picker when defaults are configured
- Add autoSelectVideoFormat / autoSelectAudioFormat helpers with closest-match
- Add buildFilteredFormatList for type-filtered format lists
- Add Media Type setting in settings UI (Ask/Video/Audio)
- Add --merge-output-format mp4 for video downloads via yt-dlp
- Fix formatLabelForDisplay to show Height fallback and Extension
- Add cookies volume mount to docker-compose.yml
- Document cookies setup and new features in README

README.md

@@ -9,14 +9,15 @@ Telegram bot for downloading media from any site yt-dlp supports.
 - DRM fallback: automatically searches YouTube when Spotify/DRM-protected content is detected
 - 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: quality, secondary format (audio/video combine), language
+- Multi-step format selection: type picker (Video/Audio/Ask), quality, secondary format (video+audio combine), language
+- Auto-select: skip the format picker entirely when defaults are set in user preferences
 - Download progress updates (with speed and ETA)
 - Cancel downloads at any time (terminates yt-dlp process)
 - Per-user quota system (daily, weekly, monthly; 0 = unlimited)
-- User preferences (default audio/video quality, language)
+- User preferences (default media type, audio/video quality, language)
 - Download history with pagination
 - Configurable file size limit (default 50 MB)
-- Cookies support for age-restricted content
+- Cookies support for age-restricted and authenticated content
 - Proxy support via HTTP_PROXY/HTTPS_PROXY env vars
 - Webhook and polling modes
 - SQLite database for persistence
@@ -52,6 +53,17 @@ Copy `.env.example` to `.env` and configure:
 | `BOT_TLS_CERT`      | empty              | TLS certificate path             |
 | `BOT_TLS_KEY`       | empty              | TLS key path                     |
 
+### Cookies (for age-restricted and authenticated content)
+
+Some sites (YouTube, Spotify, etc.) require cookies for age-restricted content. To set up:
+
+1. Install a browser extension that exports cookies in Netscape format (e.g., "Get cookies.txt" for Chrome/Firefox).
+2. Log into the site with a throwaway account.
+3. Export cookies to a file named `cookies.txt` in the project root.
+4. Set `COOKIES_FILE=/cookies.txt` in your `.env` file.
+
+For Docker, the cookie file is automatically mounted from `./cookies.txt` (see `docker-compose.yml`).
+
 ## Running
 
 ### Polling mode (default)