feat: apply terminal reconciliation cleanup

internal/client/agent/handshake_test.go

@@ -8,6 +8,7 @@ import (
 
 	rvboxv1 "github.com/rvbox/rvbox/gen/go/rvbox/v1"
 	"github.com/rvbox/rvbox/internal/agentproto"
+	"github.com/rvbox/rvbox/internal/domain"
 	"google.golang.org/protobuf/proto"
 	"google.golang.org/protobuf/types/known/timestamppb"
 )
@@ -64,11 +65,35 @@ func TestReconcileSnapshot_HP_SES_08(t *testing.T) {
 	}
 }
 
+func TestApplyReconcileResult_HP_SES_12(t *testing.T) {
+	t.Parallel()
+	active := "019c46f1-1d02-7000-8000-000000000062"
+	terminal := "019c46f1-1d02-7000-8000-000000000063"
+	store := &reconcileStore{}
+	terminated, err := ApplyReconcileResult(context.Background(), store, &rvboxv1.ReconcileResult{
+		TerminateLocalIssueUuids:       []string{active},
+		DiscardLocalTerminalIssueUuids: []string{terminal},
+	}, time.Date(2026, time.September, 6, 0, 0, 0, 0, time.UTC))
+	if err != nil || len(terminated) != 1 || terminated[0].String() != active || len(store.discarded) != 1 || store.discarded[0].String() != terminal {
+		t.Fatalf("ApplyReconcileResult = terminated=%v discarded=%v err=%v", terminated, store.discarded, err)
+	}
+	if _, err := ApplyReconcileResult(context.Background(), store, &rvboxv1.ReconcileResult{TerminateLocalIssueUuids: []string{active}, DiscardLocalTerminalIssueUuids: []string{active}}, time.Now()); !errors.Is(err, ErrInvalidReconcileResult) {
+		t.Fatalf("overlapping result error = %v", err)
+	}
+}
+
 type fakeTransport struct {
 	written []byte
 	read    []byte
 }
 
+type reconcileStore struct{ discarded []domain.UUID }
+
+func (store *reconcileStore) DiscardTerminal(_ context.Context, issue domain.UUID, _ time.Time) error {
+	store.discarded = append(store.discarded, issue)
+	return nil
+}
+
 func (transport *fakeTransport) Write(_ context.Context, value []byte) error {
 	transport.written = append([]byte(nil), value...)
 	return nil