fix: floor positive sub-seconds to 1s

[zachsmith1]

This pull request improves the domain verification controller logic to handle sub-second requeue intervals more robustly and ensures immediate verification attempts are scheduled correctly. It also adds a new test to verify the updated requeue behavior.

Verification requeue logic improvements:

• In domain_controller.go, the requeue logic now floors any sub-second RequeueAfter values to a minimum of 1 second, preventing zero-duration requeues that could cause issues.
• The controller now schedules the first verification attempt immediately when a new verification is required, ensuring prompt processing without waiting for an external trigger.

Testing enhancements:

• Added TestVerification_RequeueFloorsSubSecondToOneSecond in domain_controller_test.go to verify that sub-second requeue intervals are correctly floored to 1 second.