fix: enforce durable Windows launch release barrier

internal/client/supervisor/windows/native_other_test.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"io"
 	"strings"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -16,6 +17,23 @@ import (
 	"github.com/rvbox/rvbox/internal/domain"
 )
 
+func TestExecProcessReleaseIsIdempotent_BH_LAUNCH_05(t *testing.T) {
+	var calls atomic.Int32
+	process := &execProcess{releaseFn: func() error {
+		calls.Add(1)
+		return errors.New("release failed")
+	}}
+	if err := process.Release(context.Background()); err == nil || err.Error() != "release failed" {
+		t.Fatalf("first release error = %v", err)
+	}
+	if err := process.Release(context.Background()); err == nil || err.Error() != "release failed" {
+		t.Fatalf("repeated release error = %v", err)
+	}
+	if got := calls.Load(); got != 1 {
+		t.Fatalf("release calls = %d, want one", got)
+	}
+}
+
 func TestPortableSupervisorCapturesOutputAndSupportsStdin_HP_SUPERVISOR_03(t *testing.T) {
 	t.Parallel()
 	manager, err := NewSupervisor(NativeOptions{MaxOutputChunk: 8, WindowsTermGrace: 10 * time.Millisecond})