Preflight batch output destinations

internal/app/batch_generation_test.go

@@ -59,6 +59,42 @@ func TestRunBatchDetailedNotifiesOnlyAfterAllOutputsExist(t *testing.T) {
 	}
 }
 
+func TestRunBatchDetailedPreflightsAllOutputPaths(t *testing.T) {
+	bundle := generationBundle(t)
+	bundle.Hourly.Periods = bundle.Hourly.Periods[:1]
+	outputDir := t.TempDir()
+	if err := os.Mkdir(filepath.Join(outputDir, "tomorrow.md"), 0o700); err != nil {
+		t.Fatal(err)
+	}
+	todayPath := filepath.Join(outputDir, "today.md")
+	const previousReport = "previous report"
+	if err := os.WriteFile(todayPath, []byte(previousReport), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	executor := &generationExecutor{}
+	promptInspectedBeforeCollection := false
+	collector := &generationCollector{
+		bundle: &bundle,
+		beforeRun: func() {
+			promptInspectedBeforeCollection = executor.promptInspections > 0
+		},
+	}
+	result, err := RunBatchDetailed(context.Background(), BatchRequest{
+		Config: generationDistributorConfig(), Batch: BatchMorning,
+		Now: generationTime("2026-05-29T08:30:00-05:00"), WorkingDir: t.TempDir(), OutputDir: outputDir,
+		Collector: collector, Executor: executor, Notifier: &generationNotifier{},
+	})
+	if err == nil || result != nil || !collector.called || !promptInspectedBeforeCollection || executor.called {
+		t.Fatalf("RunBatchDetailed() result/error/collection/inspection/execution = %#v/%v/%t/%t/%t", result, err, collector.called, promptInspectedBeforeCollection, executor.called)
+	}
+	if data, readErr := os.ReadFile(todayPath); readErr != nil || string(data) != previousReport {
+		t.Fatalf("earlier output = %q, error = %v", data, readErr)
+	}
+	if info, statErr := os.Stat(filepath.Join(outputDir, "tomorrow.md")); statErr != nil || !info.IsDir() {
+		t.Fatalf("blocked output info/error = %#v/%v", info, statErr)
+	}
+}
+
 func generationDistributorConfig() config.Config {
 	cfg := generationConfig()
 	cfg.Notify.Distributor.Enabled = true