Fix Python version specification in YAML metadata

- Quote python_version to prevent YAML parsing as float
- Ensures Docker uses correct Python 3.10 image instead of 3.1

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

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

README.md

@@ -6,7 +6,7 @@ colorTo: purple
 sdk: gradio
 sdk_version: 4.44.1
 app_file: app.py
-python_version: 3.10
+python_version: "3.10"
 pinned: false
 license: apache-2.0
 short_description: 'Transform UI screenshots into design tokens'