`next.config.ts` breaks when using import aliases

Link to the code that reproduces this issue

https://github.com/Larsv94/tsconfig-alias-import-repro

To Reproduce

1. Start the application in development (next dev) or build the application (next build)

Current vs. Expected behavior

When building or starting the application with next dev the commands fail with "Error: Cannot find module './src/config/utils/someUtils'" because of someConfig.ts import someUtils.ts via an import alias.

It does work when someConfig.ts uses a relative import (included in example)

Expect import aliases to work as well

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Pro
  Available memory (MB): 32476
  Available CPU cores: 28
Binaries:
  Node: 20.18.1
  npm: 10.8.2
  Yarn: 4.5.3
  pnpm: N/A
Relevant Packages:
  next: 15.1.2 // Latest available version is detected (15.1.2).
  eslint-config-next: 15.1.2
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.7.2
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Developer Experience, TypeScript

Which stage(s) are affected? (Select all that apply)

next dev (local), next build (local)

Additional context

No response

Start with the linked reproduction and inspect next.config.ts, someConfig.ts, and someUtils.ts, then run next dev and next build to reproduce the alias failure. Done means both commands resolve the aliased import successfully while the relative-import case continues to work.