fix: pin pydantic<2.11 to prevent Gradio schema crash

Pydantic 2.11+ generates boolean values in JSON schemas where
gradio_client expects dicts, causing "argument of type 'bool' is
not iterable" in get_api_info(). Pinning pydantic<2.11 avoids
the incompatibility.

Ref: https://github.com/gradio-app/gradio/issues/11084

https://claude.ai/code/session_01TGQvouqnomLvJVhu7TZXGP

requirements.txt

@@ -1,3 +1,4 @@
 gradio==5.12.0
+pydantic<2.11
 httpx>=0.27.0
 Pillow>=10.0.0