feat: mount Flask WSGI + Gradio on unified FastAPI ASGI app

feat: add Gradio entrypoint, Caddy reverse proxy, and SLM integration

refactor!: hosted-model-only core, Drive report delivery, shared harnesses

refactor: modernize codebase to Pure Agentic RAG with live Vercel REST tools and Google Python Style Guide standards

Integrate LangChain financial data tools and connect to live Vercel REST data provider

Restructured the directory structure and updated coding format as PEP8