feat(string): Implement UTF-8 string conversion and validation functions - #2528

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: dorny/paths-filter@de90cc6fb38fc0963ad72b210f1f284cd68cea36. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/