fix(upscaler): replace GradioNode with FnNode that calls API with single path

fix(upscaler): add Image to path FnNode so Phips/Upscaler receives filepath string

docs: Generalize the README's short description for AI tools.

feat: Add multiple free AI tools to the workflow, including upscaler, image generation, and text-to-3D, and update the README to document them.

docs: Add troubleshooting advice for persistent HTML errors in Hugging Face Spaces.

docs: README SDK usage and API access for Gradio

initial commit