feat(logistics): waitlist populate UI + confirmations-tab un-confirm/re-invite actions

- waitlist-card: AddToWaitlistForm sub-component wires finalist.addToWaitlist (category + project pickers sourced from listEnrollmentCandidates, filtered to exclude confirmed/waitlisted projects; appends at next rank)
- confirmations-tab: fix dead-end empty-state copy to reference Grand Final round Overview tab
- confirmations-tab: CONFIRMED rows → Un-confirm button (AlertDialog with required reason, calls finalist.unconfirm)
- confirmations-tab: DECLINED/EXPIRED rows → Re-invite button (calls enrollFinalists EMAIL mode via liveFinalRoundId from listEnrollmentCandidates)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/admin/grand-finale/waitlist-card.tsx

@@ -1,5 +1,6 @@
 'use client'
 
+import { useState } from 'react'
 import { trpc } from '@/lib/trpc/client'
 import { toast } from 'sonner'
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card'
@@ -17,7 +18,14 @@ import {
   AlertDialogTitle,
   AlertDialogTrigger,
 } from '@/components/ui/alert-dialog'
-import { ListOrdered, Loader2 } from 'lucide-react'
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from '@/components/ui/select'
+import { ListOrdered, Loader2, PlusCircle } from 'lucide-react'
 import { formatEnumLabel } from '@/lib/utils'
 import type { CompetitionCategory } from '@prisma/client'
 
@@ -25,6 +33,145 @@ interface Props {
   programId: string
 }
 
+function AddToWaitlistForm({ programId }: { programId: string }) {
+  const utils = trpc.useUtils()
+  const [category, setCategory] = useState<string>('')
+  const [projectId, setProjectId] = useState<string>('')
+
+  const { data: candidatesData, isLoading: loadingCandidates } =
+    trpc.finalist.listEnrollmentCandidates.useQuery({ programId })
+
+  const { data: waitlistData } = trpc.finalist.listWaitlist.useQuery({ programId })
+
+  const addMutation = trpc.finalist.addToWaitlist.useMutation({
+    onSuccess: () => {
+      toast.success('Project added to waitlist')
+      utils.finalist.listWaitlist.invalidate({ programId })
+      utils.finalist.listEnrollmentCandidates.invalidate({ programId })
+      setProjectId('')
+    },
+    onError: (err) => toast.error(err.message),
+  })
+
+  // Build set of project IDs already on the waitlist
+  const waitlistedProjectIds = new Set(
+    (waitlistData ?? [])
+      .filter((e) => e.status === 'WAITING' || e.status === 'PROMOTED')
+      .map((e) => e.projectId),
+  )
+
+  // Candidates per selected category — exclude confirmed/waitlisted
+  const categoryData = candidatesData?.categories.find((c) => c.category === category)
+  const availableCandidates = (categoryData?.candidates ?? []).filter(
+    (c) =>
+      !waitlistedProjectIds.has(c.projectId) &&
+      c.confirmationStatus !== 'CONFIRMED',
+  )
+
+  // Category options (only categories that have candidates)
+  const categoryOptions = (candidatesData?.categories ?? []).filter(
+    (c) =>
+      c.candidates.some(
+        (p) =>
+          !waitlistedProjectIds.has(p.projectId) &&
+          p.confirmationStatus !== 'CONFIRMED',
+      ),
+  )
+
+  // Derive the next rank for the selected category
+  const currentMaxRank = Math.max(
+    0,
+    ...(waitlistData ?? [])
+      .filter((e) => e.category === category)
+      .map((e) => e.rank),
+  )
+  const nextRank = currentMaxRank + 1
+
+  const canSubmit = !!category && !!projectId && !addMutation.isPending
+
+  if (loadingCandidates) return <Skeleton className="h-10 w-full" />
+
+  return (
+    <div className="border-t pt-4">
+      <div className="mb-2 flex items-center gap-2 text-sm font-medium">
+        <PlusCircle className="text-muted-foreground h-4 w-4" />
+        Add to waitlist
+      </div>
+      <div className="flex flex-wrap items-end gap-2">
+        <div className="min-w-[160px]">
+          <Select
+            value={category}
+            onValueChange={(v) => {
+              setCategory(v)
+              setProjectId('')
+            }}
+          >
+            <SelectTrigger className="h-9 text-sm">
+              <SelectValue placeholder="Category" />
+            </SelectTrigger>
+            <SelectContent>
+              {categoryOptions.length === 0 ? (
+                <SelectItem value="__none__" disabled>
+                  No eligible categories
+                </SelectItem>
+              ) : (
+                categoryOptions.map((c) => (
+                  <SelectItem key={c.category} value={c.category}>
+                    {formatEnumLabel(c.category)}
+                  </SelectItem>
+                ))
+              )}
+            </SelectContent>
+          </Select>
+        </div>
+        <div className="min-w-[220px] flex-1">
+          <Select
+            value={projectId}
+            onValueChange={setProjectId}
+            disabled={!category || availableCandidates.length === 0}
+          >
+            <SelectTrigger className="h-9 text-sm">
+              <SelectValue placeholder={category ? 'Select project' : 'Choose category first'} />
+            </SelectTrigger>
+            <SelectContent>
+              {availableCandidates.length === 0 ? (
+                <SelectItem value="__none__" disabled>
+                  No eligible projects
+                </SelectItem>
+              ) : (
+                availableCandidates.map((c) => (
+                  <SelectItem key={c.projectId} value={c.projectId}>
+                    {c.title}
+                    {c.country ? ` · ${c.country}` : ''}
+                  </SelectItem>
+                ))
+              )}
+            </SelectContent>
+          </Select>
+        </div>
+        <Button
+          size="sm"
+          disabled={!canSubmit}
+          onClick={() =>
+            addMutation.mutate({
+              programId,
+              category: category as CompetitionCategory,
+              projectId,
+              rank: nextRank,
+            })
+          }
+        >
+          {addMutation.isPending ? (
+            <Loader2 className="h-4 w-4 animate-spin" />
+          ) : (
+            'Add at end'
+          )}
+        </Button>
+      </div>
+    </div>
+  )
+}
+
 const STATUS_LABEL: Record<string, { label: string; variant: 'default' | 'secondary' | 'outline' | 'destructive' }> = {
   WAITING: { label: 'Waiting', variant: 'outline' },
   PROMOTED: { label: 'Promoted', variant: 'default' },
@@ -65,10 +212,11 @@ export function WaitlistCard({ programId }: Props) {
             Per-category ranked waitlist. Auto-cascades when a finalist declines or expires.
           </CardDescription>
         </CardHeader>
-        <CardContent>
-          <p className="text-muted-foreground py-6 text-center text-sm">
+        <CardContent className="space-y-4">
+          <p className="text-muted-foreground py-4 text-center text-sm">
             No waitlist entries yet.
           </p>
+          <AddToWaitlistForm programId={programId} />
         </CardContent>
       </Card>
     )
@@ -161,6 +309,7 @@ export function WaitlistCard({ programId }: Props) {
             </div>
           </div>
         ))}
+        <AddToWaitlistForm programId={programId} />
       </CardContent>
     </Card>
   )