Concept
Authenticate, price, proxy, receipt
A gateway sits in front of an origin: it authenticates the caller’s delegation/1 chain to a trusted root, evaluates a pay-policy before the call, proxies to the origin, and emits a signed receipt per action.
Pinned to
bastion — the commercial gatewayThe canonical source this concept is taught from. If it moves, the lesson is regenerated — teaching is pinned to code, not retyped.
On the frontier
No course teaches this concept yet — it is a named gap on the content graph, not a hole nobody sees. A gap is the roadmap, not an embarrassment: the count only falls by teaching.