Added VRAM purge toggles to INPUT_TYPES:

Added VRAM purge toggles to INPUT_TYPES:

purge_cache: Clears CUDA cache during cleanup (default: True)
purge_models: Aggressively unloads all models from VRAM using comfy.model_management.unload_all_models() (default: False)
Updated setup_parallel method signature to accept purge_cache and purge_models parameters

Store purge preferences on the model: target_model._parallel_purge_cache and target_model._parallel_purge_models

Enhanced cleanup_parallel_model function to:

Read the purge flags from the model attributes
Conditionally run comfy.model_management.unload_all_models() if purge_models is True
Conditionally clear CUDA cache and soft empty cache based on purge_cache setting
Multi-GPU cache clearing (iterates through all CUDA devices)
The purge settings persist with the model and are applied when the parallel processing resources are cleaned up (either when the node is re-run with new settings or when the model is garbage collected).