zagent 0.0.228

• zagent -p --browser-use now preflights the resolved kernel for
  playwright-core before spending the turn: when the runtime cannot
  resolve it (e.g. the desktop-bundle 3.12.1 kernel, whose headless
  browser support needs the app-managed runtime), a stderr warning
  names the limitation up front instead of failing mid-turn. The flag
  still forwards verbatim — the warning is advisory, not a gate.