agents-md does not detect version properly if ranges are used

[emonty]

Link to the code that reproduces this issue

https://codesandbox.io/p/sandbox/optimistic-star-2nq57m

To Reproduce

Run npx @next/codemod@canary agents-md --output AGENTS.md in a repo with a range provided for next.

Current vs. Expected behavior

If I run npx @next/codemod@canary agents-md --output AGENTS.md in a repo using ^16 for next, the code detects version 16 and tries to download it, which is both incorrect and does not work:

$ npx @next/codemod@canary agents-md --output AGENTS.md

Downloading Next.js 16 documentation to .next-docs...
Failed to pull docs: Could not find documentation for Next.js v16. This version may not exist on GitHub yet.

Provide environment information

Operating System:
  Platform: linux
  Arch: x64
  Version: #12-Ubuntu SMP PREEMPT_DYNAMIC Fri Jan  9 20:46:52 UTC 2026
  Available memory (MB): 31021
  Available CPU cores: 22
Binaries:
  Node: 24.12.0
  npm: 11.6.2
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  next: 16.1.6 // Latest available version is detected (16.1.6).
  eslint-config-next: N/A
  react: 19.2.4
  react-dom: 19.2.4
  typescript: 5.9.3
Next.js Config:
  output: standalone

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

Not sure

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

next dev (local)

Additional context

No response