fix: 🐛 make sure that sourced paths are available to subsequent build steps

[joelostblom]

Description

For seedcase-project/seedcase-soil#43, I think the main issue is with the website build recipe, rather than the recent changes for soil. I believe that source will only put executables on path for the current shell, but each github action step runs in its own subshell. To persist executables across subshells, we would need to add them to path as per the docs. This should allow for format_output_for_docs() to find the seedcase executable when it is run in a later github action step.

Closes seedcase-project/seedcase-soil#43

This PR needs an in-depth review.

---

Note that I'm not 100% sure this is the fix because I'm unsure how to test it as I don't think I can trigger the Netlify build. Locally, you can reproduce by explicitly using a minimal path without seedcase-flower:

QUARTO="$(command -v quarto)"
env \
  QUARTO_PYTHON="$PWD/.venv/bin/python3" \
  PATH="/usr/bin:/bin" \
  "$QUARTO" render docs/guide/cli.qmd --execute

And "fix it" by instead running the following:

QUARTO="$(command -v quarto)"
env \
  QUARTO_PYTHON="$PWD/.venv/bin/python3" \
  PATH="$PWD/.venv/bin:/usr/bin:/bin" \
  "$QUARTO" render docs/guide/cli.qmd --execute

I moved my earlier general comment to #467

[lwjohnst86]

Yea, I'm not sure this will work either but let's try 😋