- Dockerfile: the prebuilt build image recipe (Ubuntu 26.04 + apt deps + aqtinstall Qt6 + KDReports), parameterized via ARG APT_PACKAGES / QT_VERSION / QT_ARCH / QT_BASE_DIR. - new_docker_build.sh: build_prebuilt_image() now runs docker build -f Dockerfile with the package list and Qt settings passed as build args, using an empty build context (the Dockerfile has no COPY/ADD).