Let the tree readers decode, give the judge the manifest's data it reads, and stop judging outside the catalogue (ADR 0578 §3, §4)

Issue 1585, S6-S8: ReadTreeManifestWritten and WithTemplatesFrom decode (the judge in mesh-delivery judges what they
answer); Manifest.Predefined, SetPredefined and FormsWritten expose what the moved judge reads; buscompose names its
removals without the catalogue's allow-list; tests outside the catalogue decode, two tree-judging tests moved.

Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL

go/compose/frombus/answer_rows_test.go

@@ -282,7 +282,7 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	f1, err := catalogue.ParseManifest(f1raw)
+	f1, err := catalogue.Decode(f1raw)
 	if err != nil {
 		t.Fatal(err)
 	}