test(conftest): make jax import lazy so tests collect without JAX

JAX is now an optional dep gated on python_version >= '3.11'. The
eager `import jax` at line 1 of test_autofit/conftest.py was breaking
pytest collection on 3.9 and 3.10. Wrap in try/except so the rest of
conftest loads. The `recreate` fixture (which uses jax._src.tree_util)
will fail if invoked without jax — that's fine, tests using it don't
run on a no-jax build.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 2 people

test_autofit/conftest.py

@@ -1,4 +1,7 @@
-import jax
+try:
+    import jax
+except ImportError:
+    jax = None
 import multiprocessing
 import os
 import shutil