UI fixes: onboarding scroll, expertise tags, jury assignments view

- Fix onboarding card overflow (overflow-hidden → overflow-x-hidden) so
  expertise step can scroll to submit button
- Reduce expertise category list height (max-h-64 → max-h-48)
- Add color dots to expertise tag options matching admin display
- Single-column layout for expertise tags (no truncation)
- Ocean background on onboarding (matches email template)
- Rewrite jury competitions page as assignment-centric grouped by round
- Conditionally show Awards nav item only when juror has award assignments

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/(auth)/onboarding/page.tsx

@@ -238,7 +238,7 @@ export default function OnboardingPage() {
   return (
     <div className="absolute inset-0 -m-4 flex items-center justify-center p-4 md:p-8 bg-[#053d57] bg-[url('https://s3.monaco-opc.com/public/ocean.png')] bg-cover bg-center bg-no-repeat">
       <AnimatedCard>
-      <Card className="w-full max-w-lg max-h-[85vh] overflow-y-auto overflow-hidden shadow-2xl">
+      <Card className="w-full max-w-lg max-h-[85vh] overflow-y-auto overflow-x-hidden shadow-2xl">
         <div className="h-1 w-full bg-gradient-to-r from-brand-blue via-brand-teal to-brand-blue" />
         {/* Progress indicator */}
         <div className="px-6 pt-6">