feat: integrate nightfox.nvim themes into Open Source Classics

* feat: integrate nightfox.nvim themes into Open Source Classics

Agent-Logs-Url: https://github.com/nisrael/psysonic/sessions/410b9047-62de-4c0b-a6bc-1dc6f8247164

Co-authored-by: nisrael <66925+nisrael@users.noreply.github.com>

* i18n: add Nightfox to theme FAQ in de + zh

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

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: nisrael <66925+nisrael@users.noreply.github.com>
Co-authored-by: Psychotoxical <dev@psysonic.app>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -32,7 +32,7 @@ Designed specifically for users hosting their own music via Navidrome or other S
 
 ## ✨ Features
 
-- 🎨 **Gorgeous UI**: A large selection of beautiful, lean themes for every taste — Open Source Classics (Catppuccin, Nord, Gruvbox), Operating Systems, Games, Movies, Series, Psysonic originals, and Mediaplayer — with smooth glassmorphism effects and micro-animations.
+- 🎨 **Gorgeous UI**: A large selection of beautiful, lean themes for every taste — Open Source Classics (Catppuccin, Nord, Gruvbox, Nightfox), Operating Systems, Games, Movies, Series, Psysonic originals, and Mediaplayer — with smooth glassmorphism effects and micro-animations.
 - ⚡ **Blazing Fast**: Built with Rust & Tauri — native audio engine (rodio), minimal RAM usage compared to typical Electron apps.
 - 🌍 **Internationalization (i18n)**: Fully translated into English, German, French, Dutch, and Chinese.
 - 📻 **Live "Now Playing"**: See what other users on your server are currently listening to in real-time.