feat: ✨ add website preview build step (#255)

# Description

I noticed this wasn't here when I updated another package via copier. We
already have it in the data template package, but I think it should be
here too?

Needs a quick review.

## Checklist

- [x] Ran `just run-all`

Author: joelostblom

template/justfile.jinja

@@ -67,16 +67,23 @@ format-python:
 format-md:
   uvx rumdl fmt --silent
 
-# Build the documentation website using Quarto
-build-website:
+# Build the Python docstrings as a section in the website using quartodoc
+build-quartodoc:
   # To let Quarto know where python is.
   export QUARTO_PYTHON=.venv/bin/python3
   # Delete any previously built files from quartodoc.
   # -f is to not give an error if the files don't exist yet.
   rm -rf docs/reference
   uv run quartodoc build
+
+# Build the documentation website using Quarto
+build-website: build-quartodoc
   uv run quarto render --execute
 
+# Preview the documentation website with automatic reload on changes
+preview-website: build-quartodoc
+  uv run quarto preview --execute
+
 # Check the commit messages on the current branch that are not on the main branch
 check-commits:
   #!/usr/bin/env bash