Replace all hardcoded muellerprints brand identity in email templates
with template variables (shopName, shopContactName, shopAddress,
shopPhone, shopEmail, shopLogoUrl, shopSecondaryLogoUrl) sourced from
env vars SHOP_NAME, SHOP_CONTACT_NAME, SHOP_ADDRESS, SHOP_PHONE,
SHOP_EMAIL, SHOP_LOGO_URL, SHOP_SECONDARY_LOGO_URL.
API documentation title/description now driven by API_TITLE and
API_DESCRIPTION env vars.
Closes#1
Source moved verbatim from mp/cms/ on 2026-04-29; mp was the first
concrete adapter consuming the libreshop toolkit. Builds and publishes
git.librete.ch/libreshop/cms on every main / v* push via the standard
.gitea/workflows/build.yml shared across libreshop components.
