Make report module overrides explicit

internal/app/app_test.go

@@ -1895,6 +1895,24 @@ reports:
 	}
 }
 
+func TestResolveGenerateRejectsInvalidProgrammaticReportOverrides(t *testing.T) {
+	cfg := config.Defaults()
+	cfg.Reports = map[string]config.ReportConfig{
+		"moon": {},
+	}
+
+	_, err := ResolveGenerate(GenerateRequest{
+		Config: cfg,
+		Report: ReportDaily,
+	}, mustParse("2026-05-29T05:00:00-05:00"))
+	if err == nil {
+		t.Fatal("ResolveGenerate() error = nil, want report override error")
+	}
+	if !strings.Contains(err.Error(), "reports.moon") {
+		t.Fatalf("ResolveGenerate() error = %q, want report override context", err.Error())
+	}
+}
+
 func moduleIDsForTest(ids []module.ID) []string {
 	out := make([]string, 0, len(ids))
 	for _, id := range ids {