A 128-pod fleet at 64 pages per pod is 8192 pages on the cards, and
keeping the queue full behind them doubles that. Three constants each
capped the chain below it, and the lowest one decides the fleet's
speed whatever the others say:

  front -> engine forwarding pool   _FWD_MAX         8192  -> 32768
  engine -> pods async client       _MAX_FLEET_POOL  16384 -> 32768
  pod thread pool (sync transport)  _MAX_POD         8192  -> 16384

All three are still sized from ocr.max_concurrency rather than set to
their ceiling, and the pod pool is still clamped to the process's task
budget, so this only stops a constant from being the binding limit.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KnfkxBpcZ1v6ypRFFyhrVM