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/components/shared/expertise-select.tsx

@@ -182,7 +182,7 @@ export function ExpertiseSelect({
       )}
 
       {/* Categories with expandable tag lists */}
-      <div className="space-y-2 max-h-64 overflow-y-auto pr-1">
+      <div className="space-y-2 max-h-48 overflow-y-auto pr-1">
         {Object.entries(filteredTagsByCategory)
           .sort(([a], [b]) => a.localeCompare(b))
           .map(([category, categoryTags]) => {
@@ -261,6 +261,10 @@ export function ExpertiseSelect({
                                 <Check className="h-2 w-2 text-white" />
                               ))}
                           </div>
+                          <span
+                            className="h-2.5 w-2.5 rounded-full shrink-0 mr-1.5"
+                            style={{ backgroundColor: tag.color || '#6b7280' }}
+                          />
                           <span className="text-xs">{tag.name}</span>
                         </Button>
                       )