refactor: centralize receipt total logic on PlatformOrder

app/Models/PlatformOrder.php

@@ -10,6 +10,24 @@ class PlatformOrder extends Model
 {
     use HasFactory;
 
+    public function receiptTotal(): float
+    {
+        // 优先读扁平字段 payment_summary.total_amount（更稳定、避免遍历 receipts）
+        $total = (float) (data_get($this->meta, 'payment_summary.total_amount') ?? 0);
+        if ($total > 0) {
+            return $total;
+        }
+
+        // 回退：遍历 payment_receipts[].amount
+        $receipts = (array) (data_get($this->meta, 'payment_receipts', []) ?? []);
+        $sum = 0.0;
+        foreach ($receipts as $r) {
+            $sum += (float) (data_get($r, 'amount') ?? 0);
+        }
+
+        return $sum;
+    }
+
     public function refundTotal(): float
     {
         // 优先读扁平字段 refund_summary.total_amount