Bundle Geist as the body sans

The design's `--ely-font-sans` is Geist; we were registering only
Newsreader. Body text everywhere fell through to GPUI's
`.SystemUIFont` (SF Pro on macOS) — too humanist for the geometric,
calm tech aesthetic the design wants.

Bundle Geist-Regular (SIL OFL 1.1, 126 KB), register it alongside
Newsreader, and set the root window's `.font_family(SANS_FAMILY)`.
SERIF_FAMILY callsites continue to override per element so headlines
keep using Newsreader.

Only Regular is bundled — GPUI synthesizes weights from the metrics,
so 500/600 still read correctly. Bold/italic file additions are a
later polish.

crates/ely_app/src/shell/chrome/mod.rs

@@ -30,5 +30,5 @@ 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 typography::{SANS_FAMILY, SERIF_FAMILY, register_serif_fonts};
 pub(crate) use wallpaper::render_wallpaper;

crates/ely_app/src/shell/chrome/typography.rs

@@ -6,12 +6,23 @@ const NEWSREADER_REGULAR: &[u8] =
     include_bytes!("../../../assets/fonts/Newsreader.ttf");
 const NEWSREADER_ITALIC: &[u8] =
     include_bytes!("../../../assets/fonts/Newsreader-Italic.ttf");
+const GEIST_REGULAR: &[u8] =
+    include_bytes!("../../../assets/fonts/Geist-Regular.ttf");
 
 pub(crate) const SERIF_FAMILY: &str = "Newsreader";
+pub(crate) const SANS_FAMILY: &str = "Geist";
 
+/// Register every bundled UI font with GPUI's text system.
+///
+/// Newsreader is the design's display serif (Hero headlines, settings
+/// titles, reading-list cover). Geist is the design's body sans —
+/// without it GPUI falls back to `.SystemUIFont` (SF Pro on macOS),
+/// which is too humanist for the geometric calm tech aesthetic the
+/// design specifies.
 pub(crate) fn register_serif_fonts(cx: &App) -> gpui::Result<()> {
     cx.text_system().add_fonts(vec![
         Cow::Borrowed(NEWSREADER_REGULAR),
         Cow::Borrowed(NEWSREADER_ITALIC),
+        Cow::Borrowed(GEIST_REGULAR),
     ])
 }

crates/ely_app/src/shell/render.rs

@@ -9,7 +9,7 @@ use gpui::{
 
 use super::chrome::command_match::visible_command_rows;
 use super::chrome::{
-    panel_bg, panel_shadow, render_command_overlay,
+    SANS_FAMILY, panel_bg, panel_shadow, render_command_overlay,
     render_topbar as render_topbar_chrome, render_wallpaper,
 };
 use super::sidebar::collapsed_sidebar_active;
@@ -69,6 +69,7 @@ impl ElyShell {
             .on_action(cx.listener(Self::on_zoom_out))
             .on_mouse_move(cx.listener(Self::on_window_mouse_move))
             .capture_key_down(cx.listener(Self::on_command_overlay_key_down))
+            .font_family(SANS_FAMILY)
             .text_color(rgb(colors::INK))
             .child(render_wallpaper(snapshot.appearance.wallpaper()))
             .child(