Replace the three `@expo-google-fonts` npm dependencies (dm-sans, dm-serif-display, geist-mono) with locally vendored TTF files under `assets/fonts/`. Update `app.json` font paths accordingly and consolidate the four separate DM Sans Android font-family entries into a single `"DM Sans"` family with multiple weight definitions. Rename font family identifiers throughout components and `global.css` to match the simplified names (`DM Sans`, `DM Serif Display`, `Geist Mono`).
jake