Add cloud-init support for automated KDE installation: include a new example user-data file for EMMC provisioning that installs KDE Plasma with touch options, sets it as the default session, and configures the on-screen keyboard. Update documentation to reflect these changes. Enhance eMMC provisioning scripts with new shrink functionality and improve error handling in backup processes.

chromium-setup/emmc-provisioning/host/build-cloudinit-image.sh

@@ -53,8 +53,12 @@ OUT_PATH="$BACKUPS_DIR/$OUT_NAME"
 
 write_status "downloading" "Downloading $(basename "$URL")…" "" ""
 XZ_FILE="$TEMP_DIR/image.img.xz"
-if ! curl -f -sS -L -o "$XZ_FILE" "$URL"; then
-    write_status "error" "" "" "Download failed"
+CURL_ERR="$TEMP_DIR/curl_err.txt"
+CURL_OPTS=(-f -L -o "$XZ_FILE" --connect-timeout 30 --max-time 7200)
+[[ "${CURL_INSECURE:-}" == "1" ]] && CURL_OPTS+=(-k)
+if ! curl "${CURL_OPTS[@]}" "$URL" 2>"$CURL_ERR"; then
+    err_detail=$(head -c 200 "$CURL_ERR" | tr '\n' ' ' | sed 's/"/\\"/g')
+    write_status "error" "" "" "Download failed: ${err_detail:-curl exited with error}"
     exit 1
 fi