Update branding

Update the Ferese symbols, appearance-specific wallpapers, and rounded wallpaper and theme previews. Bundle Figtree and add the Ferese name to the website header.

Verified configuration, theme, Settings, wallpaper and installer tests, both UI renderers, the static site build, and browser layouts.

shell/ferese-settings/src/theme_controls.rs

@@ -249,8 +249,8 @@ impl App {
         let list = crate::navigation::gallery_list(appearance, custom);
         for chunk in 0..self.family_sections.indices(custom).len().div_ceil(3) {
             let content = widget::responsive(move |size| {
-                // Three previews: 200:126 image, caption, and tile padding.
-                let height = ((size.width - 12.) / 3. - 16.).max(0.) * 126. / 200. + 34.;
+                // Three borderless previews, with names overlaid inside each image.
+                let height = ((size.width - 12.) / 3.).max(0.) * 126. / 200.;
                 let content: Element<'_, Message> = if self.visible_rows.contains(&(list, chunk)) {
                     self.theme_gallery_row(chunk, appearance, custom)
                 } else {