求助：AttributeError: module 'umap' has no attribute 'UMAP'

**Summary[问题简述（一句话）]**
在Windows上运行出现问题：module 'umap' has no attribute 'UMAP'
在训练声码器和启动demo时都出现了这个问题

**Env & To Reproduce[复现与环境]**
```
Traceback (most recent call last):
File "D:\MockingBird\encoder_train.py", line 46, in
train(**vars(args))
File "D:\MockingBird\encoder\train.py", line 100, in train
vis.draw_projections(embeds, utterances_per_speaker, step, projection_fpath)
File "D:\MockingBird\encoder\visualizations.py", line 164, in draw_projections
reducer = umap.UMAP()
AttributeError: module 'umap' has no attribute 'UMAP'
```

Start with encoder/visualizations.py at the umap.UMAP() call and reproduce the traceback through encoder_train.py. Check why the imported umap module lacks UMAP, then verify that encoder training and the demo no longer raise this AttributeError.

Written by the indexing model from the issue text.