fix: Increase rank icon sizes for better visibility

- sm: 6x6 → 10x10 (used in scoreboard tables)
- md: 8x8 → 12x12
- lg: 12x12 → 16x16

The icons were too small to see details at 6x6 pixels.
Now properly visible in the Rating column of match scoreboards.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/lib/components/ui/RankIcon.svelte

@@ -37,9 +37,9 @@
 	};
 
 	const sizeClasses = {
-		sm: 'h-6 w-6',
+		sm: 'h-10 w-10',
-		md: 'h-8 w-8',
+		md: 'h-12 w-12',
-		lg: 'h-12 w-12'
+		lg: 'h-16 w-16'
 	};
 
 	const labelSizeClasses = {