PCM build 263

🆕 Nuove funzionalità

• add human-readable cron explainer and close other/right tab actions
• add multi-format session exporter, group health check and clone-edit
• add mremoteng importer, quick session switcher and tab pinning

🐛 Correzioni di bug

• resolve subprocess import, terminal highlight, cluster freeze and cleanup leaks
• report new connection dialog errors
• restore new connection actions