Add legacy support for encryption and decryption methods in AES CyriptoService provider

[MayMeow]

closes #29

This pull request add better compatibilty with javascript encrypted data.

[Copilot]

Pull Request Overview

Adds a legacy flag to the AES CryptoService provider to support JavaScript–compatible payload formats.

• Extended encrypt and decrypt methods with a bool $legacy parameter to switch IV/TAG ordering.
• Factored payload construction into buildPayload and parsing into parsePayload.
• Updated tests to verify both default and legacy encryption/decryption flows.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/AESCryptoServiceProvider.php	Added legacy parameter, buildPayload/parsePayload methods, and updated docblocks
tests/AESCryptoServiceProviderTest.php	Added legacy-encryption test cases and decrypt(..., legacy: true) assertion

Comments suppressed due to low confidence (3)

src/AESCryptoServiceProvider.php:161

• [nitpick] The single-letter variable $c is not descriptive. Rename it to $cipherText for clarity.

$c = base64_decode($encryptedData);

tests/AESCryptoServiceProviderTest.php:19

• [nitpick] Add spaces around the = operator to match coding style ($encryptedText = ...).

$encryptedText= $csp->encrypt($plainText, legacy: true);

src/AESCryptoServiceProvider.php:152

• [nitpick] Merge the $legacy param description onto the same line (e.g. @param bool $legacy True = IV-TAG-EncryptedData; false = IV-EncryptedData-TAG).

@param bool $legacy