fix(Cookie): validate raw cookie values

[gr8man]

Description
When a Cookie is created with raw: true, values containing characters rejected by PHP's setrawcookie() (control characters, whitespace, tabs, commas, semicolons, and null bytes) previously bypassed validation during instantiation and only failed later when emitted.

This PR adds fail-fast validation in Cookie (__construct(), withValue(), withRaw(), and fromHeaderString()) to match setrawcookie() constraints:

• Adds validateValue() to check against invalid raw characters
• Adds CookieException::forInvalidCookieValue() and language string
• Adds comprehensive unit test coverage for all rejected characters and fromHeaderString()
• Updates User Guide and changelog

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide