Measured on Yggdrasil: loading by repo id leaves the model's _name_or_path
equal to the Llama repo id, so prepare_for_tokenization wraps the text in
the chat header and the vector matches assembly A (cosine 1.0, 0.909 to the
reference B). Loading from the snapshot paths reproduces the reference.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>