fix windows line endings in pasted key and rclone remote mount hint

setup.sh

@@ -88,8 +88,8 @@ case "$KEY_CHOICE" in
     chmod 700 "$SSH_DIR"
 
     echo "Paste the private key content below, then press ENTER and CTRL+D:"
-    KEY_CONTENT=$(cat)
-    echo "$KEY_CONTENT" > "$KEY_PATH"
+    KEY_CONTENT=$(cat | tr -d '\r')
+    printf '%s\n' "$KEY_CONTENT" > "$KEY_PATH"
     chown armbian:armbian "$KEY_PATH"
     chmod 600 "$KEY_PATH"
     info "Key saved to $KEY_PATH"