fix: multiple issues with queue daemon and agent forking

1. daemon: use $WORKTREES_DIR instead of $HOME/.kugetsu-worktrees
   - Worktrees are created in ~/.kugetsu/worktrees but daemon was checking ~/.kugetsu-worktrees
   - This caused cmd_start to be called when cmd_continue should have been

2. load_agent_env: add fallback to pm-agent.env
   - When dev.env and default.env don't exist, fallback to pm-agent.env
   - Ensures GITEA_TOKEN is available

3. Remove '&& disown' pattern that causes 'no such job' errors
   - nohup already makes process immune to SIGHUP
   - disown was causing errors because job context was lost

skills/kugetsu/scripts/kugetsu-config.sh

@@ -53,5 +53,9 @@ load_agent_env() {
         set -a
         source "$ENV_DIR/default.env"
         set +a
+    elif [ -f "$ENV_DIR/pm-agent.env" ]; then
+        set -a
+        source "$ENV_DIR/pm-agent.env"
+        set +a
     fi
 }