fix: destroy --base -y fails with 'target is required' (issue #183)

Removed erroneous code that set target="" when target="--base".
This caused the early exit at 'if [ -z "$target" ]' to trigger
before reaching the actual --base handling at line 517.

skills/kugetsu/scripts/kugetsu-session.sh

@@ -479,10 +479,6 @@ cmd_destroy() {
     local target="${1:-}"
     local force=false
     
-    if [ "$target" = "--base" ]; then
-        target=""
-    fi
-    
     if [ "$2" = "-y" ]; then
         force=true
     fi