GitHub September ship log: HydraFusion, new Copilot models, star history API

Choosing Project HydraFusion in Copilot's model picker selects a system that coordinates multiple models rather than a single model. GitHub's September ship log says the research preview is now available in the GitHub Copilot app and in VS Code, and that it orchestrates multiple models. This gives users one selectable entry through which to try multi-model orchestration. The announcement establishes that access and design choice; it does not explain how the models divide the work or provide a measured advantage over selecting one model directly.