Clarify checkpoint training differences

Document bundled prompt-conditioned demos

Require prompt-conditioned VocalRender inference

Link CrawlSinger-OS and document model variants

docs: add audio demo link

Emphasize VocalRender architecture in model card

Update VocalRender model card and inference guide

Move VocalRender files from root into VocalRender subfolder

Add VocalRender variant subfolder

Document independent variant subfolders

Upload VocalRender-Pro variant step 160000

Upload VocalRender checkpoint step 20000

Document VocalRender model variants

Document VocalRender and VocalRender-Pro variants

Add Apache-2.0 license

Rename model to VocalRender-Pro

initial commit