Fix: Collection rate respects branch filter

Without branch filtering, the collection rate showed global stats even
when viewing a specific branch. Now filters invoices by branch via
their associated payments.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Livewire/Financial/FinancialOverview.php

@@ -278,11 +278,19 @@ private function getRevenueBySource($from, $to): array
 
     private function getCollectionRate($from, $to): array
     {
-        $invoiced = Invoice::whereBetween('issue_date', [$from, $to])->sum('total_amount');
-        $collected = Invoice::whereBetween('issue_date', [$from, $to])->sum('paid_amount');
+        $invoicedQuery = Invoice::whereBetween('issue_date', [$from, $to]);
+        $overdueQuery = Invoice::where('status', 'overdue');
 
-        $overdue = Invoice::where('status', 'overdue')->sum('due_amount');
-        $overdueCount = Invoice::where('status', 'overdue')->count();
+        if ($this->branch_id) {
+            $invoicedQuery->whereHas('payments', fn ($q) => $q->where('branch_id', $this->branch_id));
+            $overdueQuery->whereHas('payments', fn ($q) => $q->where('branch_id', $this->branch_id));
+        }
+
+        $invoiced = (clone $invoicedQuery)->sum('total_amount');
+        $collected = (clone $invoicedQuery)->sum('paid_amount');
+
+        $overdue = (clone $overdueQuery)->sum('due_amount');
+        $overdueCount = (clone $overdueQuery)->count();
 
         return [
             'invoiced' => $invoiced,