Fix custom node blocker for multi-GPU inference using multi-processing

[SolitaryThinker]

Why these changes are needed

We have created a set of custom ComfyUI nodes around FastVideo, a framework for multi-GPU video generation using sequence parallelism.

This fixes import failures that were occurring when child processes attempted to import modules, since spawned processes get their own Python interpreter and don't inherit the same import context as the parent process.

Custom Node: https://github.com/kevin314/ComfyUI-FastVideo

Changes

Adds the directory containing main.py to Python's module search path to ensure spawned processes from multiprocessing can correctly find and import local modules.

We don't want to have users install a comfyui fork so would like to upstream this fix

Thanks

[bigcat88]

Hello. Did you tried to modify PYTHONPATH environment variable for that, does it helps in your case?