[BUG] npm publish --dry-run should detect name similarity conflicts before actual publish

Is there an existing issue for this?

• I have searched the existing issues

This issue exists in the latest npm version

• I am using the latest npm

Current Behavior

Current behavior
This has bugged me for a while, npm view returns 404 (name is free). npm publish --dry-run completes successfully. But npm publish fails with:
npm error code E403
npm error 403 Forbidden - Package name too similar to existing package

Why this matters
By the time the 403 hits, the developer has already:
Named their GitHub repo
Written the README
Potentially published blog posts or shared links

The current UX creates a false sense of safety. --dry-run explicitly promises to do "everything publish would do except actually publishing" — but it skips the one check that matters most for a new package.
Suggested fix
Run the similarity check as part of npm publish --dry-run and surface it as a warning or error before the actual publish attempt.

If nobodys willing to fix this, Ill take this up, since I believe this was raised earlier as well, but nothing was implemented.

Expected Behavior

Either npm publish --dry-run should run the similarity check and surface the conflict early, or npm view / the registry API should expose a dedicated endpoint to check name similarity so developers can verify before building, creating a GitHub repo, or writing any code.

Steps To Reproduce

Environment

• npm: 11.9.0
• Node.js: 24.14.0
• OS Name: Ubuntu

Start by tracing the npm publish --dry-run entry point and compare its validation flow with the checks performed during an actual publish. Confirm where the existing package-name similarity conflict is detected, then make dry-run surface that conflict before publishing and verify the behavior with a focused test.