Register a module only from the repository the catalogue builds it from

An agent could make a repository of its own, or fork one the mesh builds
from, commit a module.json naming sudo or mesh-host, and ask the build verb
for it: the outcome was registered under that name, and the next push made
whoever wrote it root on every node (novox/hq ADR 0266 §7, the review of
2026-10-09). The trunk rule checked the trunk of the repository built, which
was the agent's.

The take-in, which every outcome reaches whichever verb asked it, now
registers a module only from its registered repository, and a new module only
from a repository the catalogue already builds from (a merge adding one);
anything else only when the build request was kept as asked at the
controller's terminal (migration 0084). Through a verb, a build of a
repository the catalogue builds nothing from is not asked at all.

cmd/mesh-controller/gate_test.go

@@ -221,7 +221,8 @@ func TestABuildThatFailsItsGateIsRolledBackOnItsFirstMachineAndGoesNoFurther(t *
 		t.Fatalf("sent again after the rollback: %v", g.sent)
 	}
 	_, _, err = takeIn(ctx, inv, link.BuildResult{ID: "build-2", Repository: "novox/mesh-catalog", Path: "modules/app",
-		Commit: "c2", Manifest: mustJSON(t, catalogue.Manifest{Module: "app", Version: "c2"})})
+		Commit: "c2", Manifest: mustJSON(t, catalogue.Manifest{Module: "app", Version: "c2"}),
+		Source: &link.SourceOnSeat{Seat: "git", Repository: "novox/mesh-catalog"}})
 	if err == nil || !strings.Contains(err.Error(), "failed its gate") {
 		t.Fatalf("the failed build was registered again: %v", err)
 	}