improve: download method on File.php

Merge pull request #60 from webrium:Add-Header-Class

feat: add header class

fix boolean message index

fix check boolean and required in process

Merge pull request #59 from webrium/improve-form-validation

Improve form validation

Merge pull request #57 from webrium/Improved-handling-of-null-values

Improved handling of null values

Update Mail.php

Merge pull request #56 from webrium/Change-require-min-php-version-to-8

Change require min php version to 8

Update Jwt.php

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