Rebuild x-arp-session-id from forterToken/arkose/ff_session_guid instead of
ranking long Cookie pairs (e.g. aux_sid=…) as opaque ARP, which caused colligo
HTTP 408. Cache IMS JWT + cookie sessions, rotate ARP on 408 retries, and keep
Playwright warm-up opt-in only (headless Forter is rejected).
Also expand synthetic ARP shape with bfp/fpjs to match live successful captures.