If in doubt, delete the uv.lock file to fix Python 3.15 dependency errors

Simon Willison reports that switching to Python 3.15 has caused occasional dependency errors. The core solution is to delete the uv.lock file, as running commands like `uv run pytest` often leaves these files behind. If the locked file pins a version of a dependency that lacks a Python 3.15 wheel, deletion typically resolves the build failure.