Not authenticated error when out of budget

Im out of budget, and i now get the error this error loading my application that uses the SDK -
```
2026-08-21 11:49:00.627 [Information] Cockpit.Features.Auth.AuthCheckFeature: Auth re-check: restarting SDK client
2026-08-21 11:49:00.627 [Information] Cockpit.Features.Sdk.CopilotClientFeature: Stopping CopilotClient
2026-08-21 11:49:10.668 [Information] Cockpit.Features.Sessions.SessionFeature: Client disconnected — resetting SDK state for active sessions
2026-08-21 11:49:10.668 [Information] Cockpit.Features.Sdk.CopilotClientFeature: Initializing CopilotClient (logLevel=info, telemetry=True)
2026-08-21 11:49:10.669 [Information] Cockpit.Features.Sessions.SessionFeature: SDK state reset complete after client disconnect
2026-08-21 11:49:10.669 [Information] Cockpit.Features.Sdk.CopilotClientFeature: SDK telemetry exporting to C:\Users\c773975\AppData\Local\Cockpit\telemetry\otel-20260821.jsonl
2026-08-21 11:49:10.669 [Information] Cockpit.Features.Sdk.CopilotClientFeature: CopilotClient.StartCliServerAsync starting Copilot CLI. CliPath=C:\Program Files\Cockpit\runtimes\win-x64\native\copilot.exe, Executable=C:\Program Files\Cockpit\runtimes\win-x64\native\copilot.exe, CliPathSource=Bundled, UseStdio=True, Port=(null)
2026-08-21 11:49:11.826 [Information] Cockpit.Features.Sdk.CopilotClientFeature: CopilotClient started successfully
2026-08-21 11:49:11.826 [Information] Cockpit.Features.Sessions.SessionFeature: Client reconnected — resuming current session
2026-08-21 11:49:11.905 [Warning ] Cockpit.Features.Auth.AuthCheckFeature: Auth check: not authenticated — Not authenticated
2026-08-21 11:49:11.905 [Warning ] Cockpit.Features.Sdk.CopilotClientFeature: JsonRpc.InvokeAsync JSON-RPC request finished. Elapsed=00:00:00.0791917, Method=models.list, RequestId=2, Status=Failed
GitHub.Copilot.RemoteRpcException: Request models.list failed with message: Not authenticated. Please authenticate first.
at GitHub.Copilot.JsonRpc.InvokeAsync[T](String method, Object[] args, CancellationToken cancellationToken, Action`1 onResponseInline)
2026-08-21 11:49:11.906 [Error ] Cockpit.Features.Models.ModelFeature: Failed to fetch model list from Copilot SDK
System.IO.IOException: Communication error with Copilot CLI: Request models.list failed with message: Not authenticated. Please authenticate first.
---> GitHub.Copilot.RemoteRpcException: Request models.list failed with message: Not authenticated. Please authenticate first.
at GitHub.Copilot.JsonRpc.InvokeAsync[T](String method, Object[] args, CancellationToken cancellationToken, Action`1 onResponseInline)
at GitHub.Copilot.JsonRpc.InvokeAsync[T](String method, Object[] args, CancellationToken cancellationToken, Action`1 onResponseInline)
at GitHub.Copilot.CopilotClient.InvokeRpcAsync[T](JsonRpc rpc, String method, Object[] args, StringBuilder stderrBuffer, CancellationToken cancellationToken, Action`1 onResponseInline)
--- End of inner exception stack trace ---
at GitHub.Copilot.CopilotClient.InvokeRpcAsync[T](JsonRpc rpc, String method, Object[] args, StringBuilder stderrBuffer, CancellationToken cancellationToken, Action`1 onResponseInline)
at GitHub.Copilot.CopilotClient.ListModelsAsync(CancellationToken cancellationToken)
at Cockpit.Features.Models.ModelFeature.GetModels(CancellationToken cancellationToken) in D:\a\Cockpit\Cockpit\src\Cockpit\Features\Models\ModelFeature.cs:line 48
```

Im out of budget on my enterprise account i get the above error.
I signed out and then into my personal account, it loads without an issue.

Im unable to add budget to my enterprise account to prove that the `Not authenticated` error is misleading/ wrong.
But I did sign back into my enterprise account still get the same error

Start at src/Cockpit/Features/Models/ModelFeature.cs line 48 and trace the models.list failure after AuthCheckFeature restarts the client. Compare the over-budget enterprise-account behavior with the successful personal-account login; done when the resulting error accurately reflects the authentication or budget state and the client recovery path is covered.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.