fix(next): inject CSS import after directives like 'use client'

Ensure the CSS import is placed after directive prologues to avoid errors such as "The 'use client' directive must be placed before other expressions."

Author: kh4f

packages/next/src/index.ts

@@ -13,5 +13,5 @@ export default function (this: { resourcePath: string }, source: string): string
 	const { transformed, css } = transform(this.resourcePath, source)
 	if (!css) return transformed
 	const base64Css = Buffer.from(css, 'utf8').toString('base64')
-	return `import 'data:text/css;base64,${base64Css}';${transformed}`
+	return transformed.replace(/^\w/m, `import 'data:text/css;base64,${base64Css}';$&`)
 }