cb61fab77b
Two new functions: - _is_artifact_row(): marks rows as artifacts if all detected tokens are single characters (scanner shadows produce dots/dashes, not words). A real vocabulary row always contains at least one 2+ char word. - _heal_row_gaps(): after removing empty/artifact rows, expands each remaining content row to the midpoint of adjacent gaps, so OCR crops are not artificially narrow. First row extends to content top_bound; last row to content bottom_bound. Applied in both build_cell_grid() and build_cell_grid_streaming() after the word_count>0 filter and before OCR. Addresses cases like: - Row 21: scan shadow → single-char artifacts → filtered before OCR - Row 23: completely empty (word_count=0) → already filtered - Row 22: real content → now expanded upward/downward to fill the space that rows 21 and 23 occupied, giving OCR the correct full height Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>