Add new mergeVisible, mergeHidden and mergeAppends methods.

[jonerickson]

This PR adds additional attribute helper methods to Eloquent models for merging visibility-related arrays, bringing them in line with existing helpers like mergeCasts, mergeFillable, and mergeGuarded.

These new methods simplify scenarios where traits need to augment a model’s configuration without overwriting existing values.

Example

Today, when adding 2FA support via a trait, you might write:

Trait: HasTwoFactorAuthentication.php

protected function initializeTwoFactorAuthentication(): void
{
    $this->setHidden(array_merge($this->getHidden(), [
        'app_authentication_secret',
        'app_authentication_recovery_codes',
    ]));

    $this->mergeCasts([
        'app_authentication_secret' => 'encrypted',
        'app_authentication_recovery_codes' => 'encrypted:array',
    ]);
}

With this PR, the hidden attributes can be merged just as cleanly as casts:

protected function initializeTwoFactorAuthentication(): void
{
    $this->mergeHidden([
        'app_authentication_secret',
        'app_authentication_recovery_codes',
    ]);

    $this->mergeCasts([
        'app_authentication_secret' => 'encrypted',
        'app_authentication_recovery_codes' => 'encrypted:array',
    ]);
}

Existing Methods

• $model->mergeCasts()
• $model->mergeFillable()
• $model->mergeGuarded()

New Methods Added

• $model->mergeVisible()
• $model->mergeHidden()
• $model->mergeAppends()