fix: lifecycle-safe logger teardown without global state

Store file handle per module, swap lifecycle logger before closing file,
return teardown errors, remove duplicate Module() func.

Co-authored-by: Cursor <cursoragent@cursor.com>

applog_test.go

@@ -0,0 +1,57 @@
+package applog_test
+
+import (
+	"bytes"
+	"io"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"gitea.auvem.com/go-toolkit/applog"
+	"gitea.auvem.com/go-toolkit/app"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestModuleConsoleOnly(t *testing.T) {
+	var buf bytes.Buffer
+	lc := app.NewLifecycle(applog.AppLogOpts{
+		ConsoleOutput:       &buf,
+		ConsoleLevel:        slog.LevelDebug,
+		DisableAnnouncement: true,
+	}.Module())
+
+	require.NoError(t, lc.Setup())
+	lc.Logger().Info("hello")
+	require.NoError(t, lc.Teardown())
+	assert.Contains(t, buf.String(), "hello")
+}
+
+func TestModuleRequiresOutput(t *testing.T) {
+	lc := app.NewLifecycle(applog.AppLogOpts{}.Module())
+	err := lc.Setup()
+	assert.Error(t, err)
+}
+
+func TestModuleFileAndTeardown(t *testing.T) {
+	dir := t.TempDir()
+	logPath := filepath.Join(dir, "app.log")
+
+	lc := app.NewLifecycle(applog.AppLogOpts{
+		ConsoleOutput:       io.Discard,
+		FileOutput:          logPath,
+		DisableAnnouncement: true,
+	}.Module())
+
+	require.NoError(t, lc.Setup())
+	lc.Logger().Info("file line")
+	require.NoError(t, lc.Teardown())
+
+	// Logger should not write to closed file after teardown
+	lc.Logger().Info("after teardown")
+
+	data, err := os.ReadFile(logPath)
+	require.NoError(t, err)
+	assert.Contains(t, string(data), "file line")
+}