Fix dashboard: Person has 'participant' (singular), not 'participants'

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

app/Livewire/Dashboard.php

@@ -108,7 +108,7 @@ public function render()
             ->orWhereRaw("EXTRACT(MONTH FROM date_of_birth) = ? AND EXTRACT(DAY FROM date_of_birth) < ?", [
                 now()->addMonth()->month, now()->day,
             ])
-            ->whereHas('participants', function ($q) use ($branchId) {
+            ->whereHas('participant', function ($q) use ($branchId) {
                 $q->where('status', 'active')
                     ->when($branchId, fn ($pq) => $pq->where('branch_id', $branchId));
             })