fix: add type definition for @ui5/webcomponents-react/styles.css (#8417)

Without the type definition file, the TypeScript 6 upgrade is throwing
errors at our styles import

Author: MarcusNotheis

config/merge-css-modules.js

@@ -4,6 +4,7 @@ import { glob } from 'glob';
 
 const cssDir = resolve(process.cwd(), 'dist', 'css');
 const cssIndexFile = resolve(cssDir, 'index.css');
+const cssIndexTypes = resolve(cssDir, 'index.d.css.ts');
 
 const cssModules = await glob(`${cssDir}/**/*.module.css`);
 
@@ -25,3 +26,10 @@ for (const cssModule of cssModules) {
 }
 
 writeFileSync(cssIndexFile, fileContent.join('\n'));
+writeFileSync(
+  cssIndexTypes,
+  `declare const css: string;
+
+export default css;
+`,
+);

packages/main/package.json

@@ -18,7 +18,10 @@
       "default": "./wrappers/index.js"
     },
     "./package.json": "./package.json",
-    "./styles.css": "./dist/css/index.css",
+    "./styles.css": {
+      "types": "./dist/css/index.d.css.ts",
+      "default": "./dist/css/index.css"
+    },
     "./dist": "./dist/index.js",
     "./dist/*": "./dist/*",
     "./dist/*.js": "./dist/*.js",