New in Agent Builder: all new agent chat, file uploads + tool registry

LangSmith Agent Builder has been updated to make agent interaction more like collaborating with a teammate. A new central "Chat" agent can access all connected tools in a workspace for ad-hoc tasks, and any conversational workflow can be turned into a reusable agent with a single click. Users can now upload files like CSVs and images directly into chats for analysis or to provide reference material. The update also introduces a centralized tool registry for easier management, authentication, and governance of all available tools.