Fix: Fix PHPStan error by chaining Stringable methods for email+IP

[Aluisio-Pires]

Problem:
$this->string('email') returns a Stringable. In the old code we did:

return Str::transliterate(
    Str::lower($this->string('email')) . '|' . $this->ip()
);

By using the . operator to append |{$this->ip()}, the Stringable was immediately cast to a plain string. PHPStan complained because the concatenation happens without casting the Stringable object to string.
Solution:
We now keep everything as a Stringable:

return $this->string('email')
            ->lower()                       // lower-case while still a Stringable
            ->append('|'.$this->ip())      // append the IP without casting
            ->transliterate()              // transliterate on the Stringable
            ->value();                     // finally cast to string

This chains all transformations on the Stringable object and only converts to a string once, which satisfies PHPStan’s type checks.