Add a shuffle button to the worksheet preview floating action bar that generates a new random seed for problem generation: - 1/3 split button design: [Download] [🎲] [▼ dropdown] - Animated dice that rolls and changes faces (2-6) during regeneration - Final dice face derived from seed, never lands on same number twice - Excludes face 1 to ensure the icon is clearly recognizable as a dice Also includes attempted fix for operator layering in Typst templates (changed operator box width to 0.5em). 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>