feat: router.back() navigation, read-only evaluation view, auth audit logging

- Convert all Back buttons platform-wide (38 files) to use router.back()
  for natural browser-back behavior regardless of entry point
- Add read-only view for submitted evaluations in closed rounds with
  blue banner, disabled inputs, and contextual back navigation
- Add auth audit logs: MAGIC_LINK_SENT, PASSWORD_RESET_LINK_CLICKED,
  PASSWORD_RESET_LINK_EXPIRED, PASSWORD_RESET_LINK_INVALID
- Learning Hub links navigate in same window for all roles
- Update settings descriptions to reflect all-user scope

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

src/app/(jury)/jury/page.tsx

@@ -623,7 +623,7 @@ async function JuryDashboardContent() {
                     <div className="rounded-lg bg-brand-teal/10 p-1.5 dark:bg-brand-teal/20">
                       <BarChart3 className="h-4 w-4 text-brand-teal" />
                     </div>
-                    <CardTitle className="text-lg">Stage Summary</CardTitle>
+                    <CardTitle className="text-lg">Round Summary</CardTitle>
                   </div>
                 </CardHeader>
                 <CardContent className="space-y-4">