refactor: connect client once at server startup via lifespan

src/tryton_mcp/server.py

@@ -2,15 +2,22 @@
 MCP Server for Naliia Module
 """
 
-from sabatron_tryton_rpc_client.client import Client
+from contextlib import asynccontextmanager
 from fastmcp import FastMCP
-from typing import List
+from typing import List, AsyncIterator
 import datetime
 
 from tryton_mcp.config import settings
 
 
-mcp = FastMCP("Tryton MCP Server")
+@asynccontextmanager
+async def server_lifespan(server: FastMCP) -> AsyncIterator[None]:
+    settings.connect()
+    yield
+    settings.disconnect()
+
+
+mcp = FastMCP("Tryton MCP Server", lifespan=server_lifespan)
 
 
 @mcp.tool()
@@ -28,9 +35,7 @@ def create_schedule(
         }
     ]
 
-    client = Client(**settings.to_dict())
-
-    client.connect()
+    client = settings.get_client()
     name = "model.naliia.schedule.create"
     args = [example_schedule, {}]
     response = client.call(name, args)
@@ -40,9 +45,7 @@ def create_schedule(
 
 @mcp.tool()
 def find_service_centers():
-    client = Client(**settings.to_dict())
-
-    client.connect()
+    client = settings.get_client()
 
     name = "model.naliia.service_center.search_read"
     args = [[[]], 0, None, None, ["name", "address.street"], {}]
@@ -53,9 +56,7 @@ def find_service_centers():
 
 @mcp.tool()
 def find_products_and_services():
-    client = Client(**settings.to_dict())
-
-    client.connect()
+    client = settings.get_client()
 
     name = "model.product.product.search_read"
     args = [