`unbundle: true` generates unexpected virtual runtime file when using `typeof import()` in exported types

[m1rn]

Reproduction link or steps

Problem Description

When using unbundle: true configuration in tsdown, exported type declarations containing direct typeof import('./module') expressions cause the build to generate an unexpected dist/_virtual/rolldown_runtime.js file. This virtual runtime file appears to be unnecessary since the typeof import() expression is purely a type operation that should be erased during compilation.

Steps to Reproduce

1. Create a tsdown.config.ts file with:

   export default {
     dts: true,
     unbundle: true
   };

2. Create a worker module:

   // worker.ts
   export function workerMethod() {}

3. Create a main file with an exported type:

   // index.ts
   export type WorkerMethodNames = keyof typeof import('./worker');

4. Run the build: tsdown build
5. Observe the output directory contains dist/_virtual/rolldown_runtime.js

Live Reproduction:
https://stackblitz.com/edit/tsdown?file=package.json

What is expected?

Not generate any virtual runtime files for pure type expressions

What is actually happening?

Generates dist/_virtual/rolldook_runtime.js containing runtime code

Any additional comments?

No response