Feature: php artisan key:rotate command

[tanthammar]

New Feature:

This PR adds a new php artisan key:rotate command and adds a safety level to the KeyGenerateCommand.

When generating a new application key, users are now prompted to optionally save the existing key before overwriting it.
This completes the Laravel 11 rotating APP_KEY feature.

Example:

When running php artisan key:generate, if an existing key is found, the user is prompted:

There is already an app key. Do you want to store the old key before generating a new one? (yes/no) [yes]:

If the user confirms, the key:rotate command is executed to save the old key before generating a new one.

Key Changes:

• Added a new shouldSaveExistingKey() method to KeyGenerateCommand to prompt users to save the existing key.
• Introduced a new RotateKeyCommand to handle the key rotation process.
• Added missing return types to improve code clarity and consistency.

Testing - help, please:

I need help with this part. I tested it locally but I don't know how to write a test that alters the .env file

Non-breaking change:

This change is fully backward-compatible and does not have any effect, unless the user opts to save the old key.

Additional thoughts/questions:

• use ConfirmableTrait trait?
• skip all confirmations, when not in production?
• skip entirely, when not in production? The command can always be used by itself...

Let me know if you’d like to refine this further!

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Yes, phpstorm AI plugin, helped me write this PR description ;)