Add `batch` command that reads a JSON array of commands from stdin and executes them sequentially against the daemon. This avoids per-command process startup overhead when AI agents run multi-step browser workflows. Supports --bail to stop on first error (default: continue all) and --json for structured output as an array of results. Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com> Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>