ARK @imageN reference-order probe — result

binding: positional (confirmed via UseAPI docs + production ARK payloads, 2026-05-30)

Resolved WITHOUT the credit-gated --live probe — the evidence is twofold and consistent:

1. Production ARK payloads (the operator's working xskill/ARK Seedance 2.0 calls) map characters to reference_images array order with positional descriptors ("Center: … Left: … Right: …") plus "keep each identical to her reference image" — and they work, demonstrating ARK honors reference order.
2. UseAPI docs (read 2026-05-30) confirm the same ordering on the other two Seedance gateways: runway-useapi imageAssetId1..11 ↔ @IMG_1..11, dreamina-useapi omni_N_imageRef ↔ @imageN. See references/video/seedance-transport-payloads.md.

Therefore POSITIONAL_BINDING = true in src/video/seedance-blocks.ts: subjectLockEntriesFromContext emits the hard @imageN slot (not the generic subject N fallback) so SUBJECT LOCK binds each character to its reference by order, across all three gateways.

The optional scripts/probes/ark-reference-order-probe.mjs --live remains available to re-confirm against a specific endpoint, but is no longer blocking — the docs + production evidence are sufficient.