Compose Multiplatform 1.12.0 adds AI agent tools, font fallback for web apps

JetBrains released Compose Multiplatform 1.12.0 with three main upgrades: 1) An experimental Model Context Protocol (MCP) server for AI coding assistants, enabling automatic UI validation during hot reloads; 2) Automatic Noto font subset downloads for web apps when encountering unsupported characters like Japanese or emoji; 3) A redesigned WindowState API for precise control over desktop window positioning and sizing. The MCP integration allows AI agents to trigger reloads, inspect semantic trees, and simulate user interactions without manual oversight.