* fix: Allow N-GPU Layers (NGL) to be set to 0 in llama.cpp
The `n_gpu_layers` (NGL) setting in the llama.cpp extension was incorrectly preventing users from disabling GPU layers by automatically defaulting to 100 when set to 0.
This was caused by a condition that only pushed `cfg.n_gpu_layers` if it was greater than 0 (`cfg.n_gpu_layers > 0`).
This commit updates the condition to `cfg.n_gpu_layers >= 0`, allowing 0 to be a valid and accepted value for NGL. This ensures that users can effectively disable GPU offloading when desired.
* fix: default ngl
---------
Co-authored-by: Louis <louis@jan.ai>