Add context packs impact analysis and message validation

toolkit/internal/gsp/project_test.go

@@ -91,6 +91,25 @@ context: Base lottery page.
 	if !foundTitle {
 		t.Fatalf("expected canvas node text to include title, got %+v", canvas.Nodes)
 	}
+
+	pack := project.PackFor("page.lottery.main", "implement", "implement", -1, 0, Filter{})
+	if pack.Summary.UnitCount != 4 {
+		t.Fatalf("pack unit count = %d", pack.Summary.UnitCount)
+	}
+	if !strings.Contains(pack.Markdown(), "GSP Context Pack") {
+		t.Fatal("expected pack markdown")
+	}
+
+	impact := project.Impact("feedback.positive", -1)
+	if impact.Summary.DirectCount != 1 {
+		t.Fatalf("impact direct count = %d", impact.Summary.DirectCount)
+	}
+	if impact.Direct[0].ID != "page.lottery.main" {
+		t.Fatalf("impact direct = %+v", impact.Direct)
+	}
+	if !strings.Contains(impact.Markdown(), "GSP Impact") {
+		t.Fatal("expected impact markdown")
+	}
 }
 
 func TestValidateMissingReference(t *testing.T) {
@@ -263,6 +282,40 @@ func TestInitAIUsageRequiresManifest(t *testing.T) {
 	}
 }
 
+func TestValidateMessage(t *testing.T) {
+	root := t.TempDir()
+	if _, err := InitProject(root, InitOptions{
+		Entry: "page.sample.main",
+	}); err != nil {
+		t.Fatal(err)
+	}
+	writeTestFile(t, root, "message.gspmsg", `gspMessageVersion: 0.1
+id: msg.sample
+from: planner
+to: implementer
+intent: implement
+entry: page.sample.main
+stage: implement
+requires:
+  - page.sample.main
+contextPack:
+  mode: implement
+  depth: -1
+`)
+	project, err := LoadProject(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	message, err := ReadMessage(project.Root, "message.gspmsg")
+	if err != nil {
+		t.Fatal(err)
+	}
+	report := project.ValidateMessage(message)
+	if !report.OK {
+		t.Fatalf("expected valid message, got %+v", report.Errors)
+	}
+}
+
 func writeTestFile(t *testing.T, root, name, content string) {
 	t.Helper()
 	path := filepath.Join(root, name)