handoff: harden config and align MVP surface

feat: Initialize search components at module level for HF Spaces

feat: Suppress asyncio event loop warnings on HF Spaces shutdown

Disable HTTP/2 in httpx client for OpenAI and DeepSeek to avoid 421 Misdirected Request errors and ensure consistent connections in HF Spaces

Refactor httpx client usage for OpenAI and DeepSeek: implement context management to prevent socket leaks and improve error logging

Enhance provider management: normalize response keys, add availability checks, and improve Gradio interface for AI providers

Clean deployment without large index files