Governed Growth, Part 3: Default-Deny for Model Capabilities

Parts 1 and 2 argued that a capability's trust boundary is a separate decision from the model's. Part 3 is the runbook that makes the decision stick: the org-policy constraints that gate partner web search and structured outputs, set once at the organization tier by gcloud and Terraform, plus the seams org-policy doesn't reach—VPC Service Controls, request-response logging, the grounding-provider…