Fixed #15600: Adds extra verification step on checkin of device if enabled

[Glukose1]

Fixes #15600

This PR implements a modal that appears when the check-in button is clicked on the asset's check-in page. The user must click a checkbox before they can check in the asset. This behaviour can be enabled or disabled in the general settings tab. The modal has two text fields. One for a general text message in the modal and one next to the checkbox. The text for these fields can also be defined on the general settings page.

Setting disabled:

Setting enabled, with text already entered:

New verification modal after clicking check-in on the asset page, the asset cannot be checked in:

Verification modal after checking the checkbox, the asset can now be checked in:

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Different values have been assigned for both settings, and both are saved correctly.
• The Checkin process has been tested with the setting enabled and disabled.

Test Configuration:

• PHP version: 8.4.16
• MySQL version: 11.8.3-MariaDB
• Webserver version: Apache/2.4.59 (Debian) & Internal Artisan Web Server
• OS version: Debian GNU/Linux 13.3 (trixie)

Checklist:

• I have read the Contributing documentation available here: https://snipe-it.readme.io/docs/contributing-overview
• I have formatted this PR according to the project guidelines: https://snipe-it.readme.io/docs/contributing-overview#pull-request-guidelines
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[snipe]

I'm not sure we'd want this at a settings level though? Also why couldn't you use the checkbox in the required custom fields on checkin/checkout?

[Glukose1]

The required custom field would work; however, I would need to ensure that every asset model where I want the additional verification has the fieldset assigned. For existing models, this is not a problem, but for newly created models, I see it being one. Especially when multiple people, with varying levels of experience, are using the system. Small things like this can easily be forgotten or overlooked in a hurry.

I personally prefer the simple solution of making it a global setting that does not need to be maintained by the user, as the custom fields would.
If people do not want the verification on every check-in, which I totally understand, they can turn off the setting, hiding the additional textboxes to keep the settings page as clean as possible. Your proposed solution using the custom fields remains available for more granular verification on checkin.