fix: enforce MAX_CONCURRENT_AGENTS limit properly (fixes #63)

skills/kugetsu/scripts/kugetsu

@@ -857,14 +857,14 @@ cmd_start() {
         remove_worktree_for_issue "$issue_ref"
         exit 1
     fi
-    trap release_agent_slot EXIT
     if [ "$DEBUG_MODE" = true ]; then
-        opencode run "$message" --fork --session "$base_session_id" --dir "$worktree_path" 2>&1 | tee "$SESSIONS_DIR/$session_file.debug.log"
+        opencode run "$message" --fork --session "$base_session_id" --dir "$worktree_path" 2>&1 | tee "$SESSIONS_DIR/$session_file.debug.log" &
     else
-        opencode run "$message" --fork --session "$base_session_id" --dir "$worktree_path" 2>&1
+        opencode run "$message" --fork --session "$base_session_id" --dir "$worktree_path" 2>&1 &
     fi
+    local child_pid=$!
+    wait $child_pid
     release_agent_slot
-    trap - EXIT
 
     local after_sessions=$(opencode session list 2>/dev/null | grep -oP '^ses_\w+' | sort)
     local new_session_id=""