fix(scripts): update chmod permissions for Linux startup script

- Change chmod from `u+x` to `+x` for node executable to apply permissions to all users
- Ensures consistent permission handling across all executables in startup script
- Aligns with existing chmod pattern used for pmhq executable

Author: linyuchen

script/start-linux.sh

@@ -1,6 +1,6 @@
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 
-chmod u+x $SCRIPT_DIR/llbot/node
+chmod +x $SCRIPT_DIR/llbot/node
 chmod +x $SCRIPT_DIR/llbot/pmhq
 
 $SCRIPT_DIR/llbot/node $SCRIPT_DIR/llbot/llonebot.js &