fix: relax huggingface-hub pin so diffusers 0.34+ can install

The previous <0.27.0 cap blocked the resolver because diffusers 0.34+
(which we need for WanVACEPipeline) requires huggingface-hub>=0.27.0.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

requirements.txt

@@ -8,7 +8,7 @@
 gradio>=4.44.0,<5.0.0
 fastapi==0.112.2
 starlette==0.37.2
-huggingface-hub<0.27.0
+huggingface-hub>=0.27.0       # diffusers 0.34+ requires this floor
 pydantic<2.9.0
 numpy>=1.24.0,<2.0.0
 Pillow>=9.5.0,<10.0.0