Add named pipeline profile composition

internal/config/pipeline_composition_test.go

@@ -237,12 +237,12 @@ func TestLoadPipelineCompositionRejectsSameFileAliasesAndImportedComposition(t *
 		}
 	})
 
-	t.Run("future profile field", func(t *testing.T) {
+	t.Run("empty profiles", func(t *testing.T) {
 		dir := t.TempDir()
 		rootPath := writePipelineSource(t, dir, "pipeline.yml", "composition:\n  profiles: {}\n")
 		_, err := LoadPipeline(rootPath)
-		if err == nil || !strings.Contains(err.Error(), "unknown composition field") || !strings.Contains(err.Error(), "profiles") {
-			t.Fatalf("LoadPipeline() error = %v, want profile field rejected before its implementation", err)
+		if err == nil || !strings.Contains(err.Error(), "must declare at least one named profile") {
+			t.Fatalf("LoadPipeline() error = %v, want empty profiles rejection", err)
 		}
 	})
 }