Add file requirements per round and super admin promotion via UI

Part A: File Requirements per Round
- New FileRequirement model with name, description, accepted MIME types, max size, required flag, sort order
- Added requirementId FK to ProjectFile for linking uploads to requirements
- Backend CRUD (create/update/delete/reorder) in file router with audit logging
- Mime type validation and team member upload authorization in applicant router
- Admin UI: FileRequirementsEditor component in round edit page
- Applicant UI: RequirementUploadSlot/List components in submission detail and team pages
- Viewer UI: RequirementChecklist with fulfillment status in file-viewer

Part B: Super Admin Promotion
- Added SUPER_ADMIN to role enums in user create/update/bulkCreate with guards
- Member detail page: SUPER_ADMIN dropdown option with AlertDialog confirmation
- Invite page: SUPER_ADMIN option visible only to super admins

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

src/app/(admin)/admin/rounds/[id]/edit/page.tsx

@@ -32,6 +32,7 @@ import {
   type Criterion,
 } from '@/components/forms/evaluation-form-builder'
 import { RoundTypeSettings } from '@/components/forms/round-type-settings'
+import { FileRequirementsEditor } from '@/components/admin/file-requirements-editor'
 import { ArrowLeft, Loader2, AlertCircle, AlertTriangle, Bell, GitCompare, MessageSquare, FileText, Calendar, LayoutTemplate } from 'lucide-react'
 import {
   Dialog,
@@ -485,6 +486,9 @@ function EditRoundContent({ roundId }: { roundId: string }) {
             </CardContent>
           </Card>
 
+          {/* File Requirements */}
+          <FileRequirementsEditor roundId={roundId} />
+
           {/* Jury Features */}
           <Card>
             <CardHeader>