GenericNodeExtractor (previously a no-op) now inspects
RETURN_TYPES to detect MODEL loaders and CONDITIONING
encoders in nodes not registered in NODE_EXTRACTORS.
- Propagate return_types from the hook layer through the
registry to GenericNodeExtractor.extract() and update().
- MODEL detection: scan ckpt_name/unet_name/model_path/
model_name/gguf_name fields, validate by extension.
- CONDITIONING detection: scan text/clip_l/t5xxl/prompt
fields, store prompt text and conditioning tensor.
- _fill_missing_metadata also checks node_cache, so
GenericNodeExtractor-handled nodes survive cache.
Update metadata registry to remove cache entries when node metadata becomes empty instead of keeping stale data. This prevents accumulation of unused cache entries and ensures cache only contains valid metadata. Added test case to verify cache behavior when LoRA configurations are removed.
