fix: correct mergeCSSConfig generic type constraint

修复了 mergeCSSConfig 的泛型约束，使其支持 Options | undefined 类型，而不是只接受 Record<string, any>。

Changes:
- 移除 mergeCSSConfig 的泛型约束 `T extends Record<string, any>`
- 改为泛型 `T` 以支持任何类型

Author: zombieJ

src/util/index.ts

@@ -158,7 +158,10 @@ export const isClientSide = canUseDom();
 /**
  * Merge CSS injection configuration with nonce support
  */
-export function mergeCSSConfig<T extends Record<string, any>>(
+/**
+ * Merge CSS injection configuration with nonce support
+ */
+export function mergeCSSConfig<T>(
   config: T,
   nonce?: string | (() => string),
 ): T {