Wraps the new POST /browser/start-raw endpoint that launches a plain
Chrome 137 instance (no GoLogin profile) with an ephemeral user-data-dir,
optional proxy (incl. authenticated via MV3 extension) and headless flag.
Server-generated profile_id (raw_<16hex>) is returned for downstream
tabs API calls and stop.

Total tools: 22 → 23.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>