fix: sessions not removed from pool on context errors (SESSION_BUSY bug)

Co-authored-by: asmyasnikov <14202262+asmyasnikov@users.noreply.github.com>

Author: Copilot

internal/xerrors/session.go

@@ -6,6 +6,13 @@ import (
 )
 
 func MustDeleteTableOrQuerySession(err error) bool {
+	// Context errors (context.Canceled, context.DeadlineExceeded) indicate that a
+	// query may still be running on the server side. The session must be invalidated
+	// to prevent SESSION_BUSY errors on subsequent requests.
+	if IsContextError(err) {
+		return true
+	}
+
 	if IsOperationError(err,
 		Ydb.StatusIds_BAD_SESSION,
 		Ydb.StatusIds_SESSION_BUSY,

internal/xerrors/session_test.go

@@ -17,6 +17,8 @@ import (
 func TestMustDeleteTableOrQuerySession(t *testing.T) {
 	t.Run("True", func(t *testing.T) {
 		for _, err := range []error{
+			context.Canceled,
+			context.DeadlineExceeded,
 			Transport(
 				//nolint:staticcheck
 				// ignore SA1019
@@ -63,8 +65,6 @@ func TestMustDeleteTableOrQuerySession(t *testing.T) {
 	t.Run("False", func(t *testing.T) {
 		for _, err := range []error{
 			fmt.Errorf("unknown error"), // retryer given unknown error - we will not operationStatus and will close session
-			context.DeadlineExceeded,
-			context.Canceled,
 			Transport(grpcStatus.Error(grpcCodes.ResourceExhausted, "")),
 			Transport(grpcStatus.Error(grpcCodes.OutOfRange, "")),
 			Operation(