Platform-wide UX fixes: assignment dialog, invalidation, settings, dashboard

1. Assignment dialog overhaul: replace raw UUID inputs with searchable
   juror Combobox (shows name, email, capacity) and multi-select project
   checklist with bulk assignment support

2. Query invalidation sweep: fix missing invalidations in
   assignment-preview-sheet (roundAssignment.execute) and
   filtering-dashboard (filtering.finalizeResults) so data refreshes
   without page reload

3. Rename Submissions tab to Document Windows with descriptive
   header explaining upload window configuration

4. Connect 6 disconnected settings: storage_provider, local_storage_path,
   avatar_max_size_mb, allowed_image_types, whatsapp_enabled,
   whatsapp_provider - all now accessible in Settings UI

5. Admin dashboard redesign: branded Editorial Command Center with
   Dark Blue gradient header, colored border-l-4 stat cards, staggered
   animations, 2-column layout, action-required panel, activity timeline

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

src/app/(admin)/admin/settings/page.tsx

@@ -9,7 +9,7 @@ import { Skeleton } from '@/components/ui/skeleton'
 import { SettingsContent } from '@/components/settings/settings-content'
 
 // Categories that only super admins can access
-const SUPER_ADMIN_CATEGORIES = new Set(['AI', 'EMAIL', 'STORAGE', 'SECURITY'])
+const SUPER_ADMIN_CATEGORIES = new Set(['AI', 'EMAIL', 'STORAGE', 'SECURITY', 'WHATSAPP'])
 
 async function SettingsLoader({ isSuperAdmin }: { isSuperAdmin: boolean }) {
   const settings = await prisma.systemSettings.findMany({