fix: resolve `@antfu/utils` types in dts output

### Description Fix type resolution for the `imports` option — it was showing as `any` in TypeScript. This PR updates the tsdown config to bundle `@antfu/utils` types in the generated `.d.ts` output: ```ts dts: { resolve: ['@antfu/utils'], }, ``` This ensures proper type inference for the imports option and exposes supported presets correctly. ### Linked Issues Fixes #606