mcp: simplify ServerSession.Close() based on review feedback

Author: fgrosse

mcp/server.go

@@ -10,7 +10,6 @@ import (
 	"encoding/base64"
 	"encoding/gob"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"iter"
 	"maps"
@@ -1125,21 +1124,13 @@ func (ss *ServerSession) Close() error {
 		//    Close is idempotent and conn.Close() handles concurrent calls correctly
 		ss.keepaliveCancel()
 	}
-
-	var connErr, mcpConnErr error
-	if err := ss.conn.Close(); err != nil {
-		connErr = fmt.Errorf("failed to close connection: %w", err)
-	}
-
-	if err := ss.mcpConn.Close(); err != nil {
-		connErr = fmt.Errorf("failed to close mcp connection: %w", err)
-	}
+	err := ss.conn.Close()
 
 	if ss.onClose != nil {
 		ss.onClose()
 	}
 
-	return errors.Join(connErr, mcpConnErr)
+	return err
 }
 
 // Wait waits for the connection to be closed by the client.