PHP 8.4 and 8.5 compatibility

[SamueleMartini]

Replaces #61 (closed due to branch protection preventing updates).

Summary

This PR adds forward-compatibility for PHP 8.4 and PHP 8.5 while keeping PHP 8.2/8.3 support.

The last PHP 8.4 pass (#34) landed in 1.9.0, but a handful of spots still rely on silent null/false coercion that becomes a hard error on PHP 8.5 (where several long-standing deprecations are being promoted to TypeErrors, e.g. passing null to internal string functions, or passing a non-parseable string to DateTime::modify()).

cc @rhoerr @dadolun95 @SamueleMartini — happy to iterate if you want to tag this as 2.1.2 after merge.

Fixes

• Plugin/Adminhtml{Category,Cms,Product}BeforeSavePlugin: cast the return value of preg_replace() to string before strtolower(). preg_replace can return null on failure, and strtolower(null) is a TypeError on PHP 8.5.
• Helper/Service::encodePageBuilderHtmlBox: cast DOMDocument::saveHTML() results to string before feeding them to html_entity_decode() / string concatenation. saveHTML() can return false; PHP 8.5 enforces the string parameter of html_entity_decode strictly.
• Helper/ModuleConfig::getTranslationExpirationDate: cast the retranslation-period scope value to int before building the DateTime::modify() expression. Previously an unset/empty config produced - days, which becomes a DateMalformedStringException on PHP 8.5.
• Setup/Patch/Data/MigrateConfigPaths: cast the legacy scope value to string before re-encrypting, since EncryptorInterface::encrypt() now requires a strict string on PHP 8.5.
• Nullable values used as array index: cast to string/int before using as array key to avoid PHP 8.5 null array key deprecation (follow-up to PHP 8.4 and 8.5 compatibility #61 feedback on PHP 8.4 and 8.5 compatibility mage-os-lab/module-widgetkit#13).
• composer.json: widen the PHP constraint to >=8.2 <8.6 so Composer resolves cleanly on PHP 8.4 and 8.5.

No behavior change on PHP 8.2/8.3 — all casts are no-ops on valid input.

Suggested tag

2.1.2 (patch — backwards compatible bug fixes only).

Test plan

• php -l on all changed files
• Manual: translate a category / product / CMS page with a populated url_key / identifier on PHP 8.5
• Manual: run the translation cron on PHP 8.5 with a valid retranslation period set

[rhoerr]

Thank you