buildTrunkPackage: add support for tailwindcss 4

[deadbaed]

Trunk supports generating css with tailwind for assets using rel="tailwind-css" in the index.html file (see trunk documentation).

Output of the tailwind CLI used to extract the version number (there is noflag to get the version, using the --help flag instead):

phil@m1ir:~/ > nix-shell -p tailwindcss_4

[nix-shell:~]$ tailwindcss --help
≈ tailwindcss v4.1.18

Usage:
  tailwindcss [--input input.css] [--output output.css] [--watch] [options…]

Options:
  -i, --input ················· Input file
  -o, --output ················ Output file [default: `-`]
  -w, --watch[=always] ········ Watch for changes and rebuild as needed, and use `always` to keep watching when stdin is closed
  -m, --minify ················ Optimize and minify the output
      --optimize ·············· Optimize the output without minifying
      --cwd ··················· The current working directory [default: `.`]
      --map ··················· Generate a source map [default: `false`]
  -h, --help ·················· Display usage information

The env variable TRUNK_TOOLS_TAILWIND expects to have the version number without the leading v.

Motivation

I use trunk with tailwind, and it's my first time packaging a trunk app with crane. I had to add the env variables in my derivation, and saw afterwards the support for SCSS and wanted to give back upstream! Thank you for this library.

Checklist

• added tests to verify new behavior
• added an example template or updated an existing one
• updated docs/API.md (or general documentation) with changes
• updated CHANGELOG.md

For the test I duplicated the existing test trunk, removed the scss file and added tailwind, let me know if I did something wrong.

[deadbaed]

Sorry, I forgot to fix the tests when I made the changes a couple of days ago.

Tests are fixed, and rebased from master.

[ipetkov]

Thanks for the contribution! I tweaked the tests a bit to simplify things (and reduce how much we need to recompile) but otherwise looks good to me!

[deadbaed]

My pleasure! Nice trick to patch the example to get tailwind, didn't thought of that! Cheers