v5.4.3 — Grandine Support

What's New in v5.4.3

• Grandine Consensus Client added (Beacon Node + integrated validator mode)
• Improved client switching (better JWT secret handling and MEV-Boost preservation)
• Better service file generation and testing infrastructure

Thanks to @b0a7 for PR #8!

Full Changelog: v5.4.2...v5.4.3