Second Opinion MCP Server

Implement the Gemini AI integration in the second-opinion server. The GEMINI_API_KEY is already configured in config.ts, but the integration needs to be built. First read server.ts to see where the "TODO: Add Gemini integration" comment is, then implement a new gemini.ts module similar to perplexity.ts that uses the Gemini API to analyze code problems and provide solutions. The Gemini API endpoint is already defined in config.ts as API_ENDPOINTS.gemini.