Validates that a license is active and the machine is registered. Used for periodic license checks.
License key in format XXXXX-XXXXX-XXXXX-XXXXX-XXXXX.
^[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}$"ABCDE-12345-FGHIJ-67890-KLMNO"
SHA-256 hash of machine identifier (64 hex characters).
^[a-f0-9]{64}$"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
License is valid. Returns signed license data.