[Bug] Unit tests create log and checkpoint files at the project root

[kalharko]

Running the project's tests with pytest localy creates a log folder and a .ckpt file.

Proposed solution

Find which tests create those files, and update them so that they are created in pytest's temporary folder for this test run.

[Scottcjn]

Opened PR #152 for this.

It redirects the Lightning config-based tests to pytest temp directories and also moves the standalone checkpoint.tar write in tests/test_multimodal_lm.py under tmp_path, so the suite stops leaving root-relative artifacts behind.

Local verification here was:

• python3 -m py_compile tests/test_lightning.py tests/test_clip.py tests/test_multimodal_lm.py
• git diff --check

I did not claim the targeted Lightning pytest runs in this environment because lightning is not installed locally and a clean venv install path tried to bootstrap a full new torch stack.