Direct Schenker Parcel EDI Integration

Added direct Schenker EDI integration for Parcel shipments in AI Commerce. Labels can now be created straight from admin without routing through Shipit. Activation requires merchant-specific My Store credentials, plus a shipping method mapped to Schenker. Installation instructions:

https://aicommerce.helpjuice.com/order-handling/miten-otat-schenker-toimitukset-kayttoon/version/1?kb_language=fi_FI