Update transformers to install from source

Install transformers from main branch since 4.56 is not yet released but KOSMOS-2.5 support requires latest version.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

requirements.txt

@@ -1,6 +1,6 @@
 gradio==4.44.0
 torch>=2.0.0
-transformers>=4.56.0
+git+https://github.com/huggingface/transformers.git
 pillow
 requests
 spaces