style: apply Prettier formatting

Run after full implementation to enforce 2-space / 100-char / single-quote
conventions across all new + adjacent files.

tests/export-css.test.js

@@ -13,14 +13,24 @@ describe('ExportCss.build', () => {
   afterAll(() => fs.rmSync(path.dirname(fakeFontPath), { recursive: true, force: true }));
 
   test('emits a self-contained CSS with embedded @font-face', () => {
-    const css = ExportCss.build({ activeFontPath: fakeFontPath, family: 'JetBrains Mono', weight: 400, ligatures: false });
+    const css = ExportCss.build({
+      activeFontPath: fakeFontPath,
+      family: 'JetBrains Mono',
+      weight: 400,
+      ligatures: false,
+    });
     expect(css).toMatch(/@font-face\s*\{[^}]*src:\s*url\('data:font\/woff2;base64,/);
     expect(css).toContain("font-family: 'JetBrains Mono'");
     expect(css).toMatch(/font-feature-settings:[^;]*liga[^;]*0/);
   });
 
   test('falls back to family-only CSS when font path is missing', () => {
-    const css = ExportCss.build({ activeFontPath: null, family: 'Fira Code', weight: 700, ligatures: true });
+    const css = ExportCss.build({
+      activeFontPath: null,
+      family: 'Fira Code',
+      weight: 700,
+      ligatures: true,
+    });
     expect(css).not.toContain('data:font/woff2;');
     expect(css).toContain("font-family: 'Fira Code'");
   });