BLD6: the real unit level's broken fixture fails in its tests alone, go vet being the lint step's

Builds: design 47 G §328, §417

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

modules/mesh-build-go/cmd/mesh-build-go/test_real_integration_test.go

@@ -71,9 +71,9 @@ func TestUnitLevelRunsTheRealGoOnTheFixtureRepositories(t *testing.T) {
 		"tagged":  {passed: true, noTests: true},
 		"empty":   {passed: true, noTests: true},
 		"slow":    {passed: true},
-		// go vet, before the tests since R4g (ADR 0529 §1), names the directory and the compiler's line; the tests still
-		// run after it (ADR 0591), and the package that does not build is their failure.
-		"broken": {failed: []string{".", "fixture/broken"}},
+		// go vet is the lint step's, not the unit level's (design 47 G §328, §417): the package that does not build is the
+		// tests' failure alone.
+		"broken": {failed: []string{"fixture/broken"}},
 	}
 	for name, w := range want {
 		home := t.TempDir()