Fix HuggingFace Spaces deployment and add GPT-5 support

Trigger HuggingFace rebuild - ensure app.py uses app_simple

Update app.py to use fast simple version instead of multi-agent pipeline

Refactor RAG Email Assistant for in-memory processing; update configurations, implement memory indexing and retrieval, enhance Gradio UI, and streamline document ingestion.

Implement modular RAG email assistant architecture

Duplicate from gradio-templates/chatbot