feat(adagents): add validate_adagents_structure helper (#708) #1500

Job	Run time
Postgres conformance tests (Postgres 16)	1m 8s
Test Python 3.11	3m 20s
AdCP storyboard runner — v3 reference seller (translator)	1m 51s
v3 reference seller — pytest (respx-mocked upstream)	40s
Validate schemas are up-to-date	3m 27s
Test Python 3.12	3m 26s
Downstream import smoke (representative consumer symbols)	26s
AdCP storyboard runner — sales-proposal-mode (proposal_finalize)	1m 9s
AdCP storyboard runner — examples/multi_platform_seller (PlatformRouter)	1m 20s
Test Python 3.13	3m 30s
AdCP storyboard runner — examples/seller_agent.py	1m 13s
Test Python 3.10	3m 35s
Validate conventional commit format	0s
	25m 5s

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