Revert to gradio 6.9.0: fixes the api_info TypeError crash

The 'TypeError: argument of type bool is not iterable' in
gradio_client's get_type() (hit whenever the UI/API client tries to
fetch /info) is a bug specific to gradio 4.36.1's older, less complete
schema-to-python-type converter — reproduced and confirmed fixed
against an equivalent component schema under gradio 6.9.0 before
applying this.

Earlier in this fix chain I'd reverted this space to 4.36.1 on the
mistaken assumption it would restore an older Python/base image (it
doesn't - HF Spaces run Python 3.13 regardless of sdk_version). That
left old, unmaintained gradio code fighting today's dependency
versions, which is what caused the HfFolder import error and this
api_info crash. Moving back to 6.9.0, matching every other space in
this org, and dropping the now-unneeded huggingface_hub<1.0 pin
(HfFolder was gradio 4.x-specific).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -4,7 +4,7 @@ emoji: 🚀
 colorFrom: red
 colorTo: yellow
 sdk: gradio
-sdk_version: 4.36.1
+sdk_version: 6.9.0
 app_file: app.py
 pinned: false
 ---

requirements.txt

@@ -8,4 +8,4 @@ scikit-learn
 torch
 pillow
 torchvision
-huggingface_hub<1.0
+huggingface_hub