[Bug]: Using `dts.bundle: true` does not fully bundle.

Version

System:
  OS: Windows 11 10.0.22631
  CPU: (20) x64 13th Gen Intel(R) Core(TM) i9-13900H
  Memory: 10.85 GB / 31.75 GB
Browsers:
  Edge: Chromium (128.0.2739.42)
  Internet Explorer: 11.0.22621.3527

npmPackages: "@rslib/core": "^0.1.0"

Details

使用 dts.bundle: true 并没有打包完全

Using dts.bundle: true does not fully bundle.

Reproduce link

https://github.com/Zhang-Wei-666/rslib-bug-report/tree/2

Reproduce Steps

运行以下命令进行构建

pnpm i && pnpm build

查看打包产物 dist/index.d.ts 中可以发现以下内容未被打包

import type { UpperCaseCharacters } from './internal';
import type { WordSeparators } from './internal';

Run the following command to build.

pnpm i && pnpm build

Please check the packaged product at dist/index.d.ts to find the following content that has not been packaged.

import type { UpperCaseCharacters } from './internal';
import type { WordSeparators } from './internal';

Start with the linked reproduction repository and run pnpm i && pnpm build. Inspect dist/index.d.ts, especially the remaining imports from ./internal, and trace the declaration-bundling entry point that produced them. Done means the generated declaration output fully bundles these types without those unresolved internal imports.