Fix Python 3.9 compatibility for HF Space (Optional type hints).

Add voice TTS, expanded tools, voice-mode chat, and ROLLBACK guide.

Adjust system prompt: skip mandatory current_datetime, inject today for web_search.

Replace DuckDuckGo web search with Tavily API.

Fix Groq tool_use_failed with retry and qwen fallback for reliable tool calls.

Force web search for current facts; improve DDGS results for office-holder queries.

fix: summary leak, timeout, wikipedia tool