feat: refine AI backend options and UI layout

fix: enable hf_oauth in metadata

fix: use valid HF Space metadata color

docs: add HF Space metadata to README.md

feat: integrate Ollama for local prompt refinement

docs: Update design and readme to reflect ComfyUI integration and .env config

docs: Update README and design doc with Gemini and Save/Load features

Initial commit: RPGPortrait Prompt Builder