T00 foundation: theme, motion, assets, icon, buttons, gallery

Theme tokens in light and dark with high contrast, a palette cross-fade,
motion curves and a damped spring, embedded Lucide icons with Inter and
JetBrains Mono, Icon, Button, IconButton, and a gallery that captures
its own window. Reviewed by codex gpt-6-astra (max): PASS in round 3.

src/assets.rs

@@ -0,0 +1,36 @@
+use std::borrow::Cow;
+
+use anyhow::Context as _;
+use gpui::{App, AssetSource, Result, SharedString};
+use rust_embed::RustEmbed;
+
+/// Icons and fonts. Pass to `Application::with_assets`.
+#[derive(RustEmbed)]
+#[folder = "assets"]
+pub struct Assets;
+
+impl AssetSource for Assets {
+    fn load(&self, path: &str) -> Result<Option<Cow<'static, [u8]>>> {
+        Ok(Self::get(path).map(|file| file.data))
+    }
+
+    fn list(&self, path: &str) -> Result<Vec<SharedString>> {
+        Ok(Self::iter()
+            .filter(|name| name.starts_with(path))
+            .map(SharedString::from)
+            .collect())
+    }
+}
+
+pub(crate) fn load_fonts(cx: &App) -> Result<()> {
+    let fonts = Assets::iter()
+        .filter(|name| name.ends_with(".ttf"))
+        .map(|name| {
+            Assets::get(&name)
+                .map(|file| file.data)
+                .with_context(|| format!("font {name} vanished from the bundle"))
+        })
+        .collect::<Result<Vec<_>>>()?;
+    log::info!("assets: registering {} fonts", fonts.len());
+    cx.text_system().add_fonts(fonts)
+}