fix: remove unnecessary rm of msg file to avoid race condition

skills/kugetsu/scripts/kugetsu-session.sh

@@ -387,29 +387,6 @@ cmd_start() {
     echo "Worktree: $worktree_path"
 }
 
-set_debug_mode() {
-    local filtered_args=()
-    local debug_mode=false
-    
-    for arg in "$@"; do
-        case "$arg" in
-            --debug)
-                debug_mode=true
-                ;;
-            *)
-                filtered_args+=("$arg")
-                ;;
-        esac
-    done
-    
-    if [ "$debug_mode" = true ]; then
-        export KUGETSU_VERBOSITY="debug"
-        echo "[DEBUG] Debug mode enabled" >&2
-    fi
-    
-    echo "${filtered_args[@]}"
-}
-
 cmd_continue() {
     local session_name=""
     local message=""