Fix redirect description persistence

[eminos]

Summary

This fixes a bug in the new redirects feature where the Description field was shown in the publish form but discarded when creating or updating a redirect.

The controller was only copying the core redirect attributes (source, destination, response_code, and enabled) onto the redirect model. Any additional blueprint fields, including description, never made it into the redirect's data payload.

Changes

• Preserve redirect blueprint data on create and update.
• Exclude system/core redirect fields from the custom data payload.
• Add regression tests for saving the description field when creating and updating redirects.

Testing

• ./vendor/bin/pint --dirty
• ./vendor/bin/phpunit tests/Redirects/CreateRedirectTest.php tests/Redirects/UpdateRedirectTest.php

[duncanmcclean]

Thanks!