[Feature]: Port "Agent Team" feature from Python to Java version

**Is your feature request related to a problem? Please describe.**
I am currently evaluating AgentScope Java for production use. I noticed that the Python version already supports the "Agent Team" feature, but this capability is currently missing in the Java version, which makes it difficult to implement similar multi-agent workflows.

**Describe the solution you'd like**
I would like to request the "Agent Team" feature to be ported to AgentScope Java. Could you please share if this is on the roadmap and if there is an estimated timeline for its release?

**Describe alternatives you've considered**
I am currently looking into using existing Java features like `SubagentDeclaration` and the A2A protocol to simulate this behavior, but a native "Agent Team" implementation would be much more efficient and maintainable.

**Additional context**
Having feature parity between Python and Java would be highly appreciated for enterprise adoption. Thanks for your great work!