Add Zenkraft Shipping v1.0.0 - #80

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Session access in hook script — review for data leakage: 122: var allShipmentRates = JSON.parse(session.privacy.zenkraftCosts);

Session access in hook script — review for data leakage: 120: if (!empty(session.privacy.zenkraftCosts)) {

Session access in hook script — review for data leakage: 104: try { allEDD = JSON.parse(session.privacy.zenkraftEDD) || {}; } catch (eddParseErr) { allEDD = {}; }