The developer's surface is a push and one file. Everything in the larger box is the platform's: generated boilerplate, a shared catalog, the stage order, the telemetry and the events.
Principle honored
Platform as a product: a small, stable contract for developers, and the engineering on the platform side.
What changes
.tekton/ files are generated at onboarding and never hand-edited.
cicd.yaml has no sync step and no second copy: it is read from the commit.
An undeclared stage never runs.
Fails fast
A bad cicd.yaml fails in validate, with a readable schema error, before any build starts.