A definition names no installation: the check, an operator's value, a context on the git seat

InstallationProblems judges every value the mesh acts on for a name under a public top-level domain
or a public address, with prose, the world's registries, resolvers and certificate authorities
exempt, and a name a resource means on purpose declared with its reason (names-on-purpose). Run by
module check and a catalogue-wide test, not yet at registration, while the declared list shrinks.
${setting:<key>} fills a file from the assignment's settings and is refused when nothing set it.
A build context may live on the git seat; the request carries the seat's clone base (novox/hq ADR
0112, ADR 0155, issues 122 and 134).

internal/link/build.go

@@ -43,6 +43,12 @@ type BuildRequest struct {
 	// written in a manifest the mesh has not read: it is inside the repository, and reading it is
 	// the build's first act.
 	Held map[string]string `json:"held,omitempty"`
+	// Seats is the clone base — `scheme://host:port` — of each seat a recipe's context may name
+	// (novox/hq ADR 0155): `git` for this mesh's own forge. Sent with the asking for the reason
+	// Held is: the context is written in a manifest the mesh has not read, and only the mesh knows
+	// which forge holds the seat here. A builder handed no base for a seat a context names refuses
+	// the build and says so.
+	Seats map[string]string `json:"seats,omitempty"`
 }
 
 // BuildResult is what a builder says back.