* Added `UnraidCheckExec` class to handle execution of the unraidcheck script and return JSON responses.
* Updated the unraidcheck script to parse query parameters for better integration with web components.
* This change maintains separation of concerns between UnraidCheck and ReplaceKey functionalities.
* Added `ReplaceKey` initialization and check to `Registration.page`, `Downgrade.page`, `Update.page`, and `unraidcheck` script.
* Ensures consistent handling of key replacement across relevant components.