feat(notify): notify-send effector with nop fallback

internal/notify/notify_test.go

@@ -0,0 +1,22 @@
+// internal/notify/notify_test.go
+package notify
+
+import (
+	"context"
+	"testing"
+)
+
+// nopNotifier must be returned when notify-send is absent, and must never error.
+func TestNopNotifierIsSilentAndSafe(t *testing.T) {
+	n := nopNotifier{}
+	if err := n.Notify(context.Background(), "title", "body"); err != nil {
+		t.Fatalf("nop Notify must return nil, got %v", err)
+	}
+}
+
+// NewNotifier always returns a usable Notifier (never nil), whatever the host.
+func TestNewNotifierNeverNil(t *testing.T) {
+	if NewNotifier() == nil {
+		t.Fatal("NewNotifier returned nil")
+	}
+}