[v4][ISSUE] tailwindcss must be a peer dependency

[rtritto]

In the Tailwind tools/plugins (eg @tailwindcss/vite), the tailwindcss dependency should be instead a peer dependency.

From comment, some advantages of using peer dependencies:

• avoid duplicate of installed dependencies (eg where tailwindcss@4.0.1 and @tailwindcss/vite@4.0.0 (that uses tailwindcss@4.0.0) are both dependencies and there are different behaviors at runtime) that:
  • can lead the singleton issues (multiple instances that can break the runtime execution)
  • reduces the size of the installed dependencies
• control and flexibility using a specific version

Related informations, reasons and examples on PRs:

• chore: move tailwindcss from dependencies to peer dependencies #15751
• chore: move tailwindcss from dependencies to peer dependencies #15973

If you agree, up this discussion and/or comment.