Fix physx test path and add pint dependency to pre-commit

- test_units.py: Use absolute path based on script location
- .pre-commit-config.yaml: Add pint to additional_dependencies

.pre-commit-config.yaml

@@ -239,6 +239,7 @@ repos:
         name: "Book: PhysX unit checks"
         entry: python book/quarto/physx/test_units.py
         language: python
+        additional_dependencies: [pint]
         pass_filenames: false
         files: ^book/quarto/contents/.*\.qmd$
 

book/quarto/physx/test_units.py

@@ -12,7 +12,12 @@ registered in pint's registry, not just a Python variable.
 """
 
 import sys
-sys.path.insert(0, "book/quarto")
+import os
+
+# Add book/quarto to path (works from any working directory)
+_script_dir = os.path.dirname(os.path.abspath(__file__))
+_quarto_dir = os.path.dirname(_script_dir)
+sys.path.insert(0, _quarto_dir)
 
 from physx.constants import *
 from physx.formulas import *