Refactor VPN configuration handling to remove device limit management

- Updated the VPN configuration commands and handlers to eliminate the device limit parameter, simplifying the configuration process.
- Adjusted related API documentation to reflect the removal of device limit management, clarifying that this setting is now handled directly in the 3x-ui by node administrators.
- Enhanced the overall codebase by removing unnecessary device limit references across various components, ensuring a cleaner and more maintainable code structure.

backend/src/PnvPanel.Domain/Configs/VpnConfig.cs

@@ -18,7 +18,6 @@ public sealed class VpnConfig : Entity
     public string ClientEmail { get; private set; } = string.Empty;
     public string ClientExternalId { get; private set; } = string.Empty;
     public VpnProtocol Protocol { get; private set; }
-    public int DeviceLimit { get; private set; }
     public long UsedUpBytes { get; private set; }
     public long UsedDownBytes { get; private set; }
     public DateTimeOffset? ExpiresAt { get; private set; }
@@ -31,7 +30,7 @@ public sealed class VpnConfig : Entity
     {
     }
 
-    public static VpnConfig Create(Guid userId, Guid inboundId, VpnProtocol protocol, string? label, int deviceLimit)
+    public static VpnConfig Create(Guid userId, Guid inboundId, VpnProtocol protocol, string? label)
     {
         return new VpnConfig
         {
@@ -42,7 +41,6 @@ public sealed class VpnConfig : Entity
             ClientEmail = GenerateClientEmail(userId),
             ClientExternalId = string.Empty,
             Label = label,
-            DeviceLimit = deviceLimit,
             Status = ConfigStatus.Active,
             SubscriptionToken = GenerateToken(),
             CreatedAt = DateTimeOffset.UtcNow,
@@ -54,8 +52,6 @@ public sealed class VpnConfig : Entity
 
     public void Rename(string? label) => Label = label;
 
-    public void SetDeviceLimit(int deviceLimit) => DeviceLimit = deviceLimit;
-
     public void Rotate(string newClientEmail, string newClientExternalId)
     {
         EnsureActive("перевыпустить");