feat: impersonation system, semi-finalist detail page, tRPC resilience

- Add super-admin impersonation: "Login As" from user list, red banner
  with "Return to Admin", audit logged start/end, nested impersonation
  blocked, onboarding gate skipped during impersonation
- Fix semi-finalist stats: check latest terminal state (not any PASSED),
  use passwordHash OR status=ACTIVE for activation check
- Add /admin/semi-finalists detail page with search, category/status filters
- Add account_reminder_days setting to notifications tab
- Add tRPC resilience: retry on 503/HTML responses, custom fetch detects
  nginx error pages, exponential backoff (2s/4s/8s)
- Reduce dashboard polling intervals (60s stats, 30s activity, 120s semi)

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

src/components/dashboard/semi-finalist-tracker.tsx

@@ -5,6 +5,8 @@ import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
 import { Button } from '@/components/ui/button'
 import { Badge } from '@/components/ui/badge'
 import { Progress } from '@/components/ui/progress'
+import Link from 'next/link'
+import type { Route } from 'next'
 import {
   Users,
   Send,
@@ -12,6 +14,7 @@ import {
   AlertCircle,
   Trophy,
   Loader2,
+  ExternalLink,
 } from 'lucide-react'
 import { trpc } from '@/lib/trpc/client'
 import { toast } from 'sonner'
@@ -44,6 +47,7 @@ type SemiFinalistTrackerProps = {
   byAward: AwardStat[]
   unactivatedProjects: UnactivatedProject[]
   editionId: string
+  reminderThresholdDays?: number
 }
 
 const categoryLabels: Record<string, string> = {
@@ -57,6 +61,7 @@ export function SemiFinalistTracker({
   byAward,
   unactivatedProjects,
   editionId,
+  reminderThresholdDays = 3,
 }: SemiFinalistTrackerProps) {
   const utils = trpc.useUtils()
   const sendReminders = trpc.dashboard.sendAccountReminders.useMutation({
@@ -97,9 +102,16 @@ export function SemiFinalistTracker({
             <Users className="h-4 w-4 text-brand-blue" />
             Semi-Finalist Tracker
           </CardTitle>
-          <Badge variant="outline" className="text-xs">
-            {totalActivated}/{totalProjects} activated
-          </Badge>
+          <div className="flex items-center gap-2">
+            <Badge variant="outline" className="text-xs">
+              {totalActivated}/{totalProjects} activated
+            </Badge>
+            <Link href={`/admin/semi-finalists?editionId=${editionId}` as Route}>
+              <Button variant="ghost" size="sm" className="h-6 px-2 text-xs">
+                See All <ExternalLink className="ml-1 h-3 w-3" />
+              </Button>
+            </Link>
+          </div>
         </div>
       </CardHeader>
       <CardContent className="space-y-4">