19b93f7762
Column detection: - Raise MIN_COVERAGE_PRIMARY 20%→35% (prevents false columns in flowing text where random gaps < 35% of rows) - Raise MIN_COVERAGE_SECONDARY 12%→20%, MIN_DISTINCT_ROWS 2→3 - Vocabulary worksheets unaffected (columns appear in >80% of rows) Graphic word filter: - Only remove words with OCR confidence < 50 inside graphic regions - High-confidence words are real text, not image artifacts - Prevents legitimate colored text from being discarded Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>