386f90fc36
- New renderDifferentialSurgical method with three strategies: - SURGICAL: Only update specific changed lines (1-2 lines per render) - PARTIAL: Clear and re-render from first change when line counts change - FULL: Clear scrollback and re-render all when changes above viewport - Preserves all content in scrollback buffer correctly - Reduces redraws from ~14 lines to ~1.3 lines for common updates - All 24 tests pass including scrollback preservation tests - Massive performance improvement: 90% reduction in unnecessary redraws