feat(decisioning): Tier 3 brand-authz dispatch gate (#350 stage 5, closes #350) #1629

Job	Run time
Validate schemas are up-to-date	4m 2s
AdCP storyboard runner — examples/seller_agent.py	1m 28s
Validate conventional commit format	11s
Postgres conformance tests (Postgres 16)	1m 24s
Test Python 3.13	4m 18s
Test Python 3.12	4m 29s
AdCP storyboard runner — examples/multi_platform_seller (PlatformRouter)	1m 43s
Test Python 3.11	4m 11s
v3 reference seller — pytest (respx-mocked upstream)	44s
Downstream import smoke (representative consumer symbols)	29s
Test Python 3.10	4m 40s
AdCP storyboard runner — v3 reference seller (translator)	1m 44s
AdCP storyboard runner — sales-proposal-mode (proposal_finalize)	1m 1s
	30m 24s

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