tsup dts doesn't follow source structure

While using dts in tsup, there seems to be that all built declaration files are bundled into one file.
What I am expecting that the generated dts structure follows the source structures.

For example, if my source structure looks like this,


And the `src/index.ts` file exports all of them like this

```tsx
export {
Badge,
Button,
} from './components
```

My expectation of dts is creating separted `d.ts` files like this.


However, by applying the dts of tsup, it creates only a single of `.d.ts` file not following above source structure. What I knew that [vite-plugin-dts](https://github.com/qmhc/vite-plugin-dts) is following the source structure like above example.

Is there any way to follow source structure of `dts` in `tsup`?
Or Is this single `d.ts` creation behavior intended for specific reason?

My tsup config that creates a single `d.ts` is as follows.

```ts
import { defineConfig } from 'tsup';
import { TsconfigPathsPlugin } from '@esbuild-plugins/tsconfig-paths';
import { vanillaExtractPlugin } from '@vanilla-extract/esbuild-plugin';

// @ts-expect-error
export default defineConfig((options) => ({
entry: ['src/index.ts'],
outDir: 'dist',
format: ['esm', 'cjs'],
dts: true,
external: ['react', 'react-dom'],
clean: true,
splitting: false,
bundle: true,
minify: !options.watch,
sourcemap: options.watch,
plugins: [
TsconfigPathsPlugin({
tsconfig: './tsconfig.json',
}),
],
esbuildPlugins: [vanillaExtractPlugin()],
}));

```

Reproduce the declaration output from the shown tsup config, beginning at the src/index.ts entry point and its re-exports. Determine whether dts with bundle: true is intended to emit one file or should preserve source structure; done should be a documented, tested behavior matching the chosen output.

Written by the indexing model from the issue text.