CrewAI sample: configuration surface

Aligned with e2e-tests/dragent/crewai/.

workflow.yaml

Piece	Field
workflow._type: crewai_agent	DRAgent runs the CrewAI integration.
llms + workflow.llm_name	Same naming pattern as other samples.

myagent.py

Define agents, tasks, the crew, and the kickoff input mapping (placeholders like {topic} / {chat_history} in task text must match the returned keys). The sample shows history opt-in and optional tools.

register.py registers the package with DRAgent.