debug_find_index_buffer scans the container for an index buffer that validates
against a capture-proven vertex buffer. For eng_02_l nothing validates with the
connectivity test on; with it off the nearest hit is exact pad-0 adjacency
(vb-ib = 144 = 72*2). The block's mean_edge/diag is 0.417 against a 0.28 cap --
the documented false positive for coarse LODs, now caught with ground truth.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
