AgentKit SDK and Demo Targets Added to Qt-UI

Update Notes

Qt-UI AgentKit now has its first SDK and demo targets in the project tree, marking the start of a dedicated AI agent product line for Qt desktop applications.

This update includes:

• Added the AgentKit SDK static library and standalone demo target.
• Added OpenAI-compatible model access, mock streaming, chat replies, tool definitions, and agent execution.
• Added tool tracing, approval flow, and Qt Widgets UI components for chat, model configuration, and trace viewing.
• Added a Device Analysis demo to show how tools, approval, and streamed responses work together.

AgentKit is designed to help Qt teams connect model interaction, tool execution, and product UI into a maintainable desktop application workflow.