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/src/PnvPanel.Application/Configs/Create/CreateVpnConfigCommandHandler.cs

@@ -4,6 +4,7 @@ using PnvPanel.Application.Common.Interfaces;
 using PnvPanel.Application.Common.Messaging;
 using PnvPanel.Application.Common.Models;
 using PnvPanel.Domain.Configs;
+using PnvPanel.Domain.Nodes;
 
 namespace PnvPanel.Application.Configs.Create;
 
@@ -39,7 +40,7 @@ public sealed class CreateVpnConfigCommandHandler(
         var node = await dbContext
             .Nodes.AsNoTracking()
             .FirstOrDefaultAsync(n => n.Id == inbound.NodeId, cancellationToken);
-        if (node is null || !node.IsEnabled)
+        if (node is null || !node.IsEnabled || node.Status == NodeStatus.Offline)
             return Result.Failure<VpnConfigDto>(ConfigErrors.NodeDisabled);
 
         var config = VpnConfig.Create(userId, inbound.Id, inbound.Protocol, command.Label);