Build sessions_spawn command payloads from JSON profiles. Use when you want reusable subagent profiles (model/thinking/timeout/cleanup/agentId/label) and command-ready JSON without executing spawn.

从JSON配置文件构建sessions_spawn命令载荷。适用于需要可重用的子代理配置（模型/思维/超时/清理/代理ID/标签）且无需执行spawn即可获得命令就绪的JSON格式。