fix: handle deprecated @astrojs/tailwind integration and update versi…

[1046prt]

Fix bunx @astrojs/upgrade failing on projects with @astrojs/tailwind

Changes

• Fixes bunx @astrojs/upgrade failing on projects with @astrojs/tailwind integration
• Prevents upgrade tool from attempting to upgrade deprecated @astrojs/tailwind to v6.0.0
• Adds proper deprecation warning and migration guidance for @astrojs/tailwind users
• Maintains compatibility with all package managers (npm, pnpm, yarn, bun)

Before

• Running bunx @astrojs/upgrade on projects with @astrojs/tailwind would fail with error: "migration tool can only be run on v3 project"
• npx @astrojs/upgrade worked fine, creating inconsistent behavior between package managers

After

• Both bunx and npx versions of @astrojs/upgrade work consistently
• Users get clear deprecation warning about @astrojs/tailwind
• Tool provides migration guidance to @tailwindcss/vite plugin
• Other packages (like Astro core) continue to upgrade normally

Testing

• Manual testing: Created test project with @astrojs/tailwind v5.1.0 and verified fix works with both:
  • node @astrojs/upgrade --dry-run (npm equivalent)
  • bun run @astrojs/upgrade --dry-run (bun equivalent)
• Integration testing: Confirmed other packages still upgrade correctly
• Error prevention: Verified the problematic Tailwind migration tool is no longer triggered

No automated tests added as this is a CLI tool fix requiring package manager interaction that's difficult to mock in unit tests. The fix is isolated to the upgrade package's dependency resolution logic.

Docs

No documentation changes needed - this is a bug fix that restores expected behavior. The upgrade tool already had built-in help and error messaging, we've just improved the handling of a specific deprecated package.

The fix automatically provides users with the correct migration documentation link: https://tailwindcss.com/docs/installation/framework-guides/astro

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Changeset needed: Yes, this is a patch fix for @astrojs/upgrade package.

Run pnpm changeset and select:

• @astrojs/upgrade (patch)
• Summary: "Fix bunx @astrojs/upgrade failing on projects with deprecated @astrojs/tailwind integration

fix: #14778
@copilot

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Latest commit: 9569c87

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