The create dialog was one tall form that scrolled as a whole, so its header
and button moved out of view. It is now steps you go through in order:
identity, instructions (AGENTS.md in a box of its own), permissions,
resources and inference, then a summary of what will be sent and what the
agent creation queues, where create is. The header, step tabs and footer stay
put and only the step's own fields scroll. A refused AGENTS.md text sends the
dialog back to its step. The request is unchanged.
