Summary

• Horizontal scrolling is now only enabled when lines in the current viewport actually overflow
• Previously, users could scroll horizontally even when viewing short lines, as long as the file contained long lines elsewhere
• When vertical scrolling brings shorter lines into view, the horizontal scroll smoothly animates back

Changes

• Add DOM-based text measurement utilities (measureTextWidth, getMaxVisibleLineWidth) for accurate line width calculation
• Modify wheel handler to calculate actual visible lines (without tokenization buffer) and only allow horizontal scroll when they overflow
• Add animateScrollLeft utility with 150ms ease-out cubic animation for smooth transitions
• Automatically clamp/reset horizontal scroll position when viewport changes

Test plan

• Open a file with some long lines and some short lines
• Scroll to short lines - horizontal scroll should be disabled
• Scroll to long lines that extend past the viewport - horizontal scroll should work
• While scrolled horizontally, scroll vertically to shorter lines - should see smooth animation back to 0