Two generic noise filters added to _ocr_single_cell():
1. Word confidence filter (conf < 30): removes low-confidence words
before text assembly. Catches trailing artifacts like "Es)" after
real text, and standalone noise from image edges.
2. Cell noise filter: clears cells whose entire text has no real
alphabetic word (>= 2 letters). Catches fragments like "E:", "3",
"u", "D", "2.77", "and )" from image areas, while keeping real
short words like "Ei", "go", "an".
Both filters apply to word-lookup AND cell-OCR fallback results.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2b1c499d54