The _shorten_filenames function was adding both the full filename and the
stem (without extension) to dropdown lists, causing models like VAEs and
text encoders to appear twice (e.g. 'ae' and 'ae.safetensors'). Now only
the stem is returned.
Backend resolution helpers (_resolve_model_name) are added to translate
stem-only names back to full filenames when loading checkpoin/vae/
text_encoder/controlnet models, ensuring backwards compatibility with
existing YAML files that store full filenames.
Mehdi Chaid