Enhance inbound management by removing MaxClients property

- Removed the MaxClients property from Inbound-related data models, including InboundDto and PublishInboundCommand.
- Updated related methods and handlers to reflect the removal of MaxClients, ensuring consistent behavior across the application.
- Adjusted API documentation and frontend components to remove references to MaxClients, streamlining the inbound publishing process.
- Enhanced logging in command handlers to handle node unavailability scenarios during user actions.
- Improved database schema and migrations to align with the updated data model.

backend/tests/PnvPanel.Application.Tests/Admin/Configs/ListAllConfigsQueryHandlerTests.cs

@@ -26,7 +26,7 @@ public class ListAllConfigsQueryHandlerTests
             null
         );
         var inbound = Inbound.FromRemote(node.Id, "1", VpnProtocol.Vless, "remark", 443);
-        inbound.Publish("Germany", [], null);
+        inbound.Publish("Germany", []);
         var config = VpnConfig.Create(userId, inbound.Id, VpnProtocol.Vless, "my-config");
 
         dbContext.Nodes.Add(node);