fix(ui): fix Storybook style parity with main app

The @tailwindcss/vite plugin only generates CSS for classes found in the
Vite module graph. In the Storybook build, many component source files
were not in the graph, producing only 70KB of CSS versus the main app's
263KB — missing data-state, data-slot, and hundreds of utility classes.

Added a storybook-specific CSS entry with @source "../../src" so
Tailwind v4 scans all component files, bringing the generated CSS to
283KB with full style parity.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

ui/storybook/.storybook/preview.tsx

@@ -23,7 +23,7 @@ import {
   storybookSidebarBadges,
 } from "../fixtures/paperclipData";
 import "@mdxeditor/editor/style.css";
-import "@/index.css";
+import "./tailwind-entry.css";
 import "./styles.css";
 
 function installStorybookApiFixtures() {

ui/storybook/.storybook/tailwind-entry.css

@@ -0,0 +1,2 @@
+@import "../../src/index.css";
+@source "../../src";