feat(help): add missing sections and questions (Device Sync, Internet Radio, CLI, Playlists, Infinite Queue, Lyrics sources, Audio device, Backup & Restore, Now Playing)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/locales/en.ts

@@ -795,6 +795,32 @@ export const enTranslation = {
     a46: 'Hot Cache (Alpha, Settings → Library) preloads the next several tracks in your queue to disk so playback starts instantly with no buffering delay — especially useful on slow or remote servers. Psysonic keeps the current track and the next 5 in cache and evicts older entries when the size limit is reached. You can set the maximum cache size and a debounce delay to avoid unnecessary fetches when skipping quickly.',
     q47: 'Can I cache a playlist for offline use?',
     a47: 'Yes. Open any playlist and click the download icon in the playlist header. All tracks are downloaded in the background — progress is shown in the offline download indicator. Once fully cached, the icon changes to a red trash icon; clicking it removes the playlist from the offline cache.',
+    q48: 'What is Infinite Queue?',
+    a48: 'When the queue runs out and Repeat is off, Psysonic silently appends random tracks from your library so playback never stops. Auto-added tracks appear below a "— Added automatically —" divider in the queue. Toggle it with the infinity icon in the queue header. You can also restrict auto-added tracks to a specific genre in Settings → Queue.',
+    q49: 'Can I control Psysonic from the command line?',
+    a49: 'Yes — the Psysonic binary doubles as a remote control for the running app. Examples: psysonic --player play / pause / next / prev, --player volume 75, --player seek 15, --player mute, --player shuffle, --player repeat off|all|one, --player star / unstar, --player rating 1-5. You can also switch servers (--player server list / set), change the audio device (--player audio-device list / set), filter the music library (--player library list / set), trigger an Instant Mix (--player mix new / append), and search (--player search track|album|artist <query>). Run psysonic --player --help for the full list. Shell completions for bash and zsh are available via psysonic completions.',
+    q50: 'How do I manage playlists?',
+    a50: 'Open "Playlists" in the sidebar. Click "New Playlist" to create one. On a playlist detail page you can drag tracks to reorder them, remove tracks with the × button, search your library to add songs, and use "Suggestions" to get smart track recommendations based on your playlist content. Right-click any track for more options.',
+    q51: 'Can I back up and restore my settings?',
+    a51: 'Yes. Settings → Backup & Restore lets you export all your settings, server profiles, themes, and keybindings to a single JSON file. Import it on another machine or after a reinstall to restore everything at once. Passwords are included in the backup — store the file securely.',
+    q52: 'How do I change the audio output device?',
+    a52: 'Settings → Audio → Output Device. Psysonic lists all available audio outputs on your system. Select the one you want — playback switches immediately. Use the refresh button next to the list if a device was connected after the app started. On Linux this uses ALSA device names; generic entries like "default" or "sysdefault" are automatically cleaned up for readability.',
+    q53: 'What is Device Sync?',
+    a53: 'Device Sync lets you copy albums, playlists, or entire artists to a USB drive or SD card for listening on other devices. Open it via "Device Sync" in the sidebar. Select a target folder on your drive, choose sources from the browser tabs, and click "Transfer to Device". Psysonic downloads the tracks from your server and writes them in the folder structure defined by the filename template.',
+    q54: 'What is the filename template in Device Sync?',
+    a54: 'The filename template controls how tracks are named and organized on the device. Use the preset buttons (Standard, Multi-Disc, Alt. Folder) or build your own using the clickable token chips: {artist}, {album}, {title}, {track_number}, {disc_number}, {year}, and / for folder separators. A live preview shows how an example track would be named.',
+    q55: 'Does Device Sync work across platforms?',
+    a55: 'Yes. The sync manifest (psysonic-sync.json) written to the device stores the filename template used during sync. When you open Device Sync on a different OS with a different template, Psysonic uses the stored template to correctly detect which files are already on the device — so albums don\'t show as pending when they are already synced.',
+    s9: 'Device Sync',
+    q56: 'What is Internet Radio?',
+    a56: 'The Internet Radio page (sidebar) lets you play any live stream directly in Psysonic. Stations are fetched from your Navidrome server — add them there via the Navidrome admin panel, or import a .pls / .m3u file. Playback uses the browser\'s built-in HTML5 audio engine rather than the Rust audio engine, so some EQ and Replay Gain settings do not apply to radio.',
+    q57: 'What stream formats does Internet Radio support?',
+    a57: 'Psysonic supports any format your system\'s audio stack can decode: MP3, AAC, OGG Vorbis, and most HLS streams. The stream is played via HTML5 <audio>, so codec support depends on the platform — MP3 and AAC work everywhere.',
+    s10: 'Internet Radio',
+    q58: 'Where does Psysonic fetch lyrics from?',
+    a58: 'Psysonic supports three lyrics sources, all configurable in Settings → Lyrics: your Navidrome server (embedded/OpenSubsonic lyrics), LRCLIB (community-contributed synced lyrics), and NetEase Cloud Music (large Chinese and international catalog). You can enable or disable each source and reorder their priority by dragging. Synced lyrics auto-scroll and support click-to-seek; plain-text lyrics are shown statically.',
+    q59: 'Is there a Now Playing view for other users?',
+    a59: 'Yes. Click the broadcast icon in the top-right header to open the "Now Playing" dropdown. It shows what other users on your Navidrome server are currently listening to, updated every 10 seconds. Your own entry disappears when you pause.',
   },
   queue: {
     title: 'Queue',