feat: Add LangGraph integration #3873

Job	Run time
Cloud (latest) (3.8, ubuntu-22.04)	1m 43s
Cloud (latest) (3.11, ubuntu-22.04)	1m 22s
Cloud (latest) (3.13, ubuntu-22.04)	2m 51s
Cloud (pinned) (3.7, ubuntu-22.04)	3m 43s
Cloud (pinned) (3.6, ubuntu-22.04)	2m 23s
Cloud (pinned) (3.11, ubuntu-22.04)	3m 32s
Cloud (pinned) (3.8, ubuntu-22.04)	3m 50s
Cloud (latest) (3.12, ubuntu-22.04)	2m 14s
Cloud (pinned) (3.13, ubuntu-22.04)	4m 58s
Cloud (pinned) (3.12, ubuntu-22.04)	2m 8s
Cloud (pinned) (3.9, ubuntu-22.04)	4m 17s
All pinned Cloud tests passed	3s
	33m 4s

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