`return_token_ids` added to the vllm entry of _ENGINE_FORWARDED_FIELDS, so a
rented pod's vLLM backend can be asked for raw vocabulary ids -- without which
the v0.3.31 repair can never fire on a RunPod-served model, which is every OCR
model on the Digesta install.

Inert by default: engine_config_for_pod skips falsey values, so adding the field
cannot change an install that has not set it.

Set on Aruba for `datalab-to/surya-ocr-2` ONLY, through its models.json `vllm`
block rather than globally. The flag changes what the `token` string inside
logprobs looks like and that install also serves qwen38-awq and diogene-alpha on
vLLM pods; nothing in coderai reads that field except the OCR repair, but a
client might, and there is no reason to find out the hard way.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PxYHWbCAjjjD7A1rhFKtaW