Extract the tools tuple from a subagent spec.
For CompiledSubAgent<ReactAgent<Types>>, resolves to Types["Tools"].
Falls back to the default (ClientTool | ServerTool)[] for SubAgent
and AsyncSubAgent.
SubagentToolsOf: T extends CompiledSubAgent<
R
> R extends ReactAgent<Types> Types["Tools"] : readonly ClientTool | ServerTool[] : readonly ClientTool | ServerTool[]