style: update BadgeNumber colors for dark theme and add validation logging

Updated the badge component's styling to use darker brand colors (text-brand-500, bg-brand-950, border-brand-900) for improved contrast in dark mode. Added console.error logging when the number prop is non-positive to aid debugging and enforce input validation.

Author: CharlyMartin

src/components/ui/badge-number.tsx

@@ -6,8 +6,9 @@ function BadgeNumber({ number }: BadgeNumberProps) {
   if (number <= 0) {
     console.error('BadgeNumber: number must be positive, received:', number)
   }
+
   return (
-    <span className="text-brand-50 bg-brand-200 border-brand-100 flex h-8 w-8 flex-shrink-0 items-center justify-center rounded-full border">
+    <span className="text-brand-500 bg-brand-950 border-brand-900 flex h-8 w-8 flex-shrink-0 items-center justify-center rounded-full border">
       {number}
     </span>
   )