docs: Document how to manage Material3 typography

To edit Android fonts, especially navigation titles and tab bar titles, you have to edit your Main.kt and edit typography settings there. This should be in the docs somewhere.

@Composable
internal fun PresentationRootView(context: ComposeContext) {
    val colorScheme = if (isSystemInDarkTheme()) ColorScheme.dark else ColorScheme.light

    val typography = androidx.compose.material3.Typography(
        // nav title (large)
        headlineLarge = androidx.compose.ui.text.TextStyle(
            fontFamily = androidx.compose.ui.text.font.FontFamily.Monospace,
            fontWeight = androidx.compose.ui.text.font.FontWeight.Bold
        ),
        // nav title (smaller)
        headlineMedium = androidx.compose.ui.text.TextStyle(
            fontFamily = androidx.compose.ui.text.font.FontFamily.Monospace,
            fontWeight = androidx.compose.ui.text.font.FontWeight.Bold
        ),
        // tab title
        labelMedium = androidx.compose.ui.text.TextStyle(
            fontFamily = androidx.compose.ui.text.font.FontFamily.Monospace,
            fontWeight = androidx.compose.ui.text.font.FontWeight.Bold
        )
    )

    androidx.compose.material3.MaterialTheme(typography = typography) {
        PresentationRoot(defaultColorScheme = colorScheme, context = context) { ctx ->
            val contentContext = ctx.content()
            Box(modifier = ctx.modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
                RootView().Compose(context = contentContext)
            }
        }
    }
}

Start with the Main.kt example in the issue and identify the repository's documentation location for Android and Material3 guidance. Document how the Typography settings control navigation and tab titles, including the shown headlineLarge, headlineMedium, and labelMedium examples; done means a newcomer can find and follow these instructions.