Bundle Newsreader serif and apply to hero text

Embeds Newsreader (variable opsz/wght, OFL-licensed) into the
ely_app binary via include_bytes!, registers it through GPUI's
text_system at startup (chrome::typography::register_serif_fonts),
and exposes the SERIF_FAMILY constant for downstream surfaces.

Apply the family to every page hero where the design uses
ely-serif: home headline, settings/appearance headline, plugin
marketplace headline, sync headline, plugin detail name, and the
home reading-list cover headline. The OFL license file ships
alongside the .ttf assets to satisfy the font's redistribution
clause.

crates/ely_app/src/main.rs

@@ -60,6 +60,9 @@ fn main() {
     application.on_open_urls(move |urls| open_url_queue.push(urls));
     application.run(move |cx: &mut App| {
         gpui_component::init(cx);
+        if let Err(error) = shell::chrome::register_serif_fonts(cx) {
+            eprintln!("ELY: failed to register serif fonts: {error}");
+        }
         cx.on_action(quit);
         bind_shortcuts(cx);
         cx.on_action(open_private_window);