refactor(ui): strip all dark: Tailwind classes (single-theme product)

Mechanical sweep of 41 files via `perl -i -pe 's{\s+dark:[\w:/\[\]\.\-]+}{}g'`.
All dark: variants were paired with light-mode counterparts already; no
elements relied on a dark:-only style.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/ui/badge.tsx

@@ -15,10 +15,10 @@ const badgeVariants = cva(
           'border-transparent bg-destructive text-destructive-foreground shadow hover:bg-destructive/80',
         outline: 'text-foreground',
         success:
-          'border-transparent bg-green-100 text-green-800 dark:bg-green-900 dark:text-green-100',
+          'border-transparent bg-green-100 text-green-800',
         warning:
-          'border-transparent bg-amber-100 text-amber-800 dark:bg-amber-900 dark:text-amber-100',
-        info: 'border-transparent bg-blue-100 text-blue-800 dark:bg-blue-900 dark:text-blue-100',
+          'border-transparent bg-amber-100 text-amber-800',
+        info: 'border-transparent bg-blue-100 text-blue-800',
       },
     },
     defaultVariants: {