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/shell/chrome/mod.rs

@@ -8,6 +8,7 @@ pub(crate) mod sidebar;
 pub(crate) mod sidebar_header;
 pub(crate) mod split_pane;
 pub(crate) mod topbar;
+pub(crate) mod typography;
 pub(crate) mod wallpaper;
 
 pub(crate) use appearance_form::render_appearance_form;
@@ -22,4 +23,5 @@ pub(crate) use split_pane::{
     render_split_pane_header,
 };
 pub(crate) use topbar::render_topbar;
+pub(crate) use typography::{SERIF_FAMILY, register_serif_fonts};
 pub(crate) use wallpaper::render_wallpaper;