Initial project scaffold: Rust egui ePub reader

- Cargo.toml with eframe, egui, epub, rfd, serde dependencies
- Source modules: app, book, font, persistence, reader, theme
- MinGW static linking config
- .gitignore for build artifacts

src/font.rs

@@ -0,0 +1 @@
+pub fn setup_fonts(_ctx: &egui::Context) {}