20_profile_selection.sh and 25_installation_confirm.sh still spoke the
old flat profile model (.profiles[], .profile.distribution,
.profile.installer.type) that the provisioning server no longer
returns - it now returns .templates[] with workspace/backend objects
(see provisioning-server's Merkmal/Blueprint/Bereitstellungsvorlage
migration). Both modules now read/write
/run/tuxflotte/assignment/template.json against the current
Bereitstellungsvorlage schema, matching 10-interactive-provisioning-flow.md.
