Improve base image validation and update Dockerfile comments for clarity

build-user-image.sh

@@ -123,7 +123,8 @@ echo "Target arch: ${TARGET_ARCH}, platform: ${PLATFORM}"
 echo "Language: ${USER_LANGUAGE}"
 echo "Version tag: ${VERSION}"
 
-if ! docker image inspect "${BASE_IMAGE}" >/dev/null 2>&1; then
+# Check if base image exists using docker images (more reliable than inspect)
+if ! docker images --format '{{.Repository}}:{{.Tag}}' | grep -q "^${BASE_IMAGE}$"; then
   echo "Base image ${BASE_IMAGE} not found locally. Build it first (e.g. ./build-base-image.sh -a ${TARGET_ARCH} -v ${VERSION})." >&2
   exit 1
 fi

files/kde-root/defaults/startwm.sh

@@ -77,5 +77,5 @@ if which nvidia-smi > /dev/null 2>&1 && ls -A /dev/dri 2>/dev/null && [ "${DISAB
   export GALLIUM_DRIVER=zink
 fi
 
-# Start DE
-exec dbus-launch --exit-with-session /usr/bin/startplasma-x11 > /dev/null 2>&1
+# Start DE (without exec to allow dbus-launch to work properly)
+dbus-launch --exit-with-session /usr/bin/startplasma-x11 > /dev/null 2>&1

files/linuxserver-kde.user.dockerfile

@@ -1,9 +1,12 @@
-ARG BASE_IMAGE
+# Base image must be provided via --build-arg BASE_IMAGE=<image>
+ARG BASE_IMAGE=scratch
 FROM ${BASE_IMAGE}
 
 ARG USER_NAME
 ARG USER_UID
 ARG USER_GID
+# Note: USER_PASSWORD is used only during image build for initial setup.
+# It is not stored in the image layers. Change password after first login.
 ARG USER_PASSWORD=""
 ARG HOST_HOSTNAME="Docker-Host"
 ARG USER_LANGUAGE="en"