- Add readingFont setting to UserSettings interface
- Create fontLoader utility to load fonts from Bunny Fonts
- Add font selector dropdown in settings with popular reading fonts
- Use CSS variable --reading-font to apply font to reader content
- Support fonts: Inter, Lora, Merriweather, Open Sans, Roboto, Source Serif 4, Crimson Text, Libre Baskerville, PT Serif
- Fonts loaded from https://fonts.bunny.net/ (GDPR-friendly)
