feat: implement backend API clients for multi-marketplace integration and frontend service layer

backend/wb_api/services/marketplace.py

@@ -0,0 +1,39 @@
+from typing import Dict, Any, List
+from ..client import WBClient
+
+class MarketplaceService:
+    """Service to handle WB FBS operations (Marketplace API)."""
+    
+    def __init__(self, client: WBClient):
+        self.client = client
+        self.base_url = WBClient.MARKETPLACE_API
+
+    def get_new_orders(self) -> Dict[str, Any]:
+        """
+        Get new orders (FBS).
+        Endpoint: /api/v3/orders/new
+        """
+        return self.client.get(self.base_url, "/api/v3/orders/new")
+
+    def get_orders(self, limit: int = 1000, next: int = 0, date_from: int = 0, date_to: int = 0) -> Dict[str, Any]:
+        """
+        Get list of orders by parameters.
+        Endpoint: /api/v3/orders
+        """
+        params = {
+            "limit": limit,
+            "next": next
+        }
+        if date_from:
+            params["dateFrom"] = date_from
+        if date_to:
+            params["dateTo"] = date_to
+            
+        return self.client.get(self.base_url, "/api/v3/orders", params=params)
+
+    def put_orders_status(self, orders: List[Dict[str, Any]]) -> Dict[str, Any]:
+        """
+        Change status of orders (e.g. to assembly).
+        Endpoint: /api/v3/orders/status
+        """
+        return self.client.post(self.base_url, "/api/v3/orders/status", data={"orders": orders})