1. n_gpu_layers kwarg: accept (and ignore) in load_model signature
so callers like llm_assist.py don't get TypeError
2. mmproj exclusion: filter out mmproj files in _find_smallest_fitting_variant
so fallback doesn't pick a tiny vision projection as the "model"
3. Shard preservation after fallback: re-discover shards for the
fallback variant instead of resetting to empty list, so split
GGUFs download all shards
4. Orphan cleanup safety: only kill llama-server processes whose
cmdline contains ".unsloth/", avoiding termination of unrelated
llama-server instances on the same machine
5. Path expression sanitization: validate repo_id format before using
it in cache directory lookups