Root cause found at T11 e2e: unclip_rect pushed corners radially from the
centroid. For a wide/short text box the diagonal is near-horizontal, so the box
barely grew in height and clipped character tops (ㄷ→ㄴ, 다→나). Rewrote unclip
as a proper per-edge polygon offset along the rect's own (u,v) axes — height and
width each grow by 2*distance, matching PaddleOCR pyclipper.
Result (synthetic-ocr-bench, real inference): mean gate CER 0.2585 → 0.0049
(clean_paragraph/korean_heavy/numbers_table/tech_terms = 0.0), beating the
0.976 PoC baseline. Big page 3.9s < 5s.
T10: dict-length-mismatch construction error + undecodable-bytes recognize error.
T11 e2e: tests/paddle_e2e.rs CER<=0.05 gate (skips cleanly when assets absent).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>