chore: stabilize lint and verify builds

backend/database/fields/orders.go

@@ -25,17 +25,19 @@ type ordersSnapshotWire struct {
 	Data json.RawMessage `json:"data"`
 }
 
-func (s *OrdersSnapshot) UnmarshalJSON(b []byte) error {
-	var w ordersSnapshotWire
-	if err := json.Unmarshal(b, &w); err == nil && (w.Kind != "" || w.Data != nil) {
-		s.Kind = w.Kind
-		s.Data = w.Data
+func (snapshot *OrdersSnapshot) UnmarshalJSON(raw []byte) error {
+	var wire ordersSnapshotWire
+	if err := json.Unmarshal(raw, &wire); err == nil && (wire.Kind != "" || wire.Data != nil) {
+		snapshot.Kind = wire.Kind
+		snapshot.Data = wire.Data
+
 		return nil
 	}
 
 	// 兼容旧结构：旧 snapshot 通常是一个扁平对象（没有 kind/data）。
-	s.Kind = "legacy"
-	s.Data = append(s.Data[:0], b...)
+	snapshot.Kind = "legacy"
+	snapshot.Data = append(snapshot.Data[:0], raw...)
+
 	return nil
 }