fix: remove output message after STDIO transport stops

When MCP clients disconnect from STDIO transport, they close STDOUT/STDERR
streams before the Laravel command completes. Attempting to output
"MCP Server (STDIO) stopped." to closed streams causes fwrite() errors.

Author: CodeWithKyrian

src/Commands/ServeCommand.php

@@ -89,8 +89,6 @@ private function handleStdioTransport(Server $server): int
             return Command::FAILURE;
         }
 
-        $this->info("MCP Server (STDIO) stopped.");
-
         return Command::SUCCESS;
     }