OpenAI Agents SDK Setup with Gemini + Native MCP Integration

Quick reference for initializing OpenAI Agents SDK with Gemini models (gemini-2.5-flash) using native MCP integration for the Todo AI Chatbot Phase 3.

CRITICAL INSIGHT: The OpenAI Agents SDK has native MCP support via MCPServerStreamableHttp. We do NOT need @function_tool wrappers! The agent connects directly to the MCP server and discovers tools automatically.