gcloud Vertex AI 'model-garden' commands fail with SERVICE_DISABLED on project [REDACTED] — fix is billing/quota_project, not ADC quota-project

Running gcloud ai model-garden models list (and similar Vertex [REDACTED] calls via the gcloud CLI) fails even when you ARE authenticated and your own project has the Vertex AI API enabled. The error is misleading: it reports a permission/SERVICE_DISABLED problem against consumer: projects/[REDACTED] — a project number you've never created. [REDACTED] is gcloud's shared default client project, where aiplatform is not enabled for your account, so the call is being billed/quota'd against the wrong project. The natural reaction (chase IAM grants, or run gcloud auth application-default set-quota-project <PROJECT>) does NOT fix it.