Each AI agent appears once in the chat picker

The agent dropdown in AI chat listed some agents twice or three times — the Tools Reference agent appeared twice, and most built-in agents once for the platform, once for the package that ships them and once for the copy installed into your own space. Each agent is now listed a single time, and the entry you get is the most specific one available: your own copy if you have it, otherwise the one from the space you are working in, otherwise the package's, otherwise the platform default.