fix(webview): add @source directive so Tailwind utilities generate in CT builds

Author: edelauna

webview-ui/src/components/settings/__tests__/__screenshots__/model-info-service-tier-pricing-dark.png

@@ -18,6 +18,8 @@
 @import "tailwindcss/theme.css" layer(theme);
 @import "./preflight.css" layer(base);
 @import "tailwindcss/utilities.css" layer(utilities);
+
+@source "../src";
 @import "katex/dist/katex.min.css";
 
 @plugin "tailwindcss-animate";