feat: Professional editor UI redesign - 3-column layout (docs | editor | sidebar) - Documents panel always visible on desktop - Import/export moved to left sidebar - Removed CTA button from nav - Replaced all emojis with SVG icons - Clean toolbar with separator - Mobile: docs stay as overlay sidebar
feat: Add AraSpell spelling correction endpoint (POST /api/spelling) with lazy model loading - Extract AraSpell pipeline into src/nlp/spelling/ (araspell_rules.py + araspell_service.py) - Pre-download AraBERT encoder-decoder + checkpoint in Dockerfile - Lazy load on first request, contextual=False to save RAM - Update health check to report spelling status