PR #4769 (e4d14992) added a module-level `from utils.models import
extract_model_size_b` to llama_cpp.py. Since core/inference/__init__.py
eagerly imports llama_cpp, the spawn subprocess now hits:
core.inference.__init__ → llama_cpp → utils.models →
model_config (line 8: `from transformers import AutoConfig`)
…before _activate_transformers_version() has a chance to prepend
.venv_t5/ to sys.path. Python caches transformers 4.57.6 in
sys.modules, and no subsequent sys.path change can override it.
Fix: replace the eager import with a thin wrapper that defers the
import to first call. This breaks the transitive chain so
transformers is not loaded until after version activation.
737017a511