[MCP SDK] Remove rector/rector dependency

Author: OskarStark

src/mcp-sdk/composer.json

@@ -22,7 +22,6 @@
         "phpstan/phpstan": "^2.1",
         "phpunit/phpunit": "^11.5",
         "symfony/console": "^6.4 || ^7.0",
-        "rector/rector": "^2.0",
         "psr/cache": "^3.0"
     },
     "suggest": {