NOJIRA: Add agent team graph

[CfromBU]

Summary

• Add AgentTeamGraph, a composed Graph that fans input to team members and collects named outputs.
• Support optional aggregation over collected team_outputs.
• Export the component from masfactory.

Test Plan

• uv run --no-sync --with pytest pytest tests/components/test_agent_team_graph.py -q (local ignored test, not committed)
• uv run --no-sync python -m py_compile masfactory/components/composed_graph/agent_team_graph.py
• git diff --check

[AckerlyLau]

A lead agent receives a task and determines how to approach it. It may handle some subtasks directly while dispatching others to subagents. Subagents complete their work and return results, which the orchestrator synthesizes into a final output.

Claude Code uses this pattern. The main agent writes code, edits files, and runs commands itself, dispatching subagents in the background when it needs to search a large codebase or investigate independent questions so work continues while results stream back. Each subagent operates in its own context window and returns distilled findings. This keeps the orchestrator's context focused on the primary task while exploration happens in parallel.

按这个描述重新实现一下 agent team。目前的实现类似 agentverse 的brainstorm，而不是 agentteam