Each VG region box is index-aligned with its own description, so the crop
can be encoded and paired with the phrase describing it -- part
correspondence by annotation, which is cross-modal supervision a deployed
system would not have. The cross-modal anchor bound goes 0.336 -> 0.359.

So the two encoders do not covary at the part level either, and no
segmentation, aggregation, kernel or backbone repairs that. The 0.805
within-text ceiling was never the cross-modal ceiling; for this encoder
pair on this corpus the cross-modal ceiling is about 0.36 against the 0.9
recovery needs.

Six representational interventions this session were chosen without a
ceiling in view -- the same error being made on the matching side at the
same time. What replaces them is a three-number screening protocol that
runs before any pipeline is built.

Co-Authored-By: Claude <noreply@anthropic.com>