feat(skin): add audio skins for HTML and React presets (#772)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

build/plugins/resolve-css-imports.mjs

@@ -0,0 +1,27 @@
+import { readFileSync } from 'node:fs';
+import { dirname, resolve } from 'node:path';
+
+/**
+ * Resolves `@import` directives in CSS content, inlining referenced files.
+ *
+ * @param {string} content - The CSS content to resolve.
+ * @param {string} baseDir - The directory to resolve relative imports from.
+ * @param {string} skinsDir - The directory to resolve `@videojs/skins` imports from.
+ * @returns {string} The resolved CSS content.
+ */
+export function resolveImports(content, baseDir, skinsDir) {
+  return content.replace(/@import\s+['"]([^'"]+)['"]\s*;/g, (_, importPath) => {
+    let file;
+
+    if (importPath.startsWith('@videojs/skins/')) {
+      file = resolve(skinsDir, importPath.replace('@videojs/skins/', ''));
+    } else if (importPath.startsWith('.')) {
+      file = resolve(baseDir, importPath);
+    } else {
+      return _;
+    }
+
+    const nested = readFileSync(file, 'utf-8');
+    return resolveImports(nested, dirname(file), skinsDir);
+  });
+}