fix: handle disposed scope during workflow instance refresh after Blazor disconnect

[Copilot]

Purpose

Prevents intermittent host crashes in Workflow Instance Viewer when a Blazor Server circuit disconnects and a timer callback continues into disposed scoped services (IServiceProvider).
This targets the ObjectDisposedException path reported from activity execution refresh calls.

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Scope

Select one primary concern:

• Bug fix (behavior change)
• Refactor (no behavior change)
• Documentation update
• Formatting / code cleanup
• Dependency / build update
• New feature

If this PR includes multiple unrelated concerns, please split it before requesting review.

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Description

Problem

A periodic refresh in WorkflowInstanceDesigner can outlive circuit lifetime. After _blazor/disconnect, refresh callbacks may still execute and attempt to resolve/use scoped services via backend API providers, triggering unhandled ObjectDisposedException and process termination.

Solution

• Targeted guard in refresh path
  • Wrap RefreshSelectedItemAsync body in try/catch (ObjectDisposedException).
• Fail-safe shutdown of periodic work
  • On disposal exception, stop the refresh timer via StopRefreshActivityStatePeriodically() to prevent repeated callbacks into disposed scope.
• No functional broadening
  • Keeps behavior unchanged in healthy circuits; only alters disconnect/disposal race handling.

Example change:

try
{
    // existing refresh flow
    SelectedActivityExecutions = await GetActivityExecutionRecordsAsync(LastActivityExecution.ActivityNodeId);
    await InvokeAsync(() =>
    {
        StateHasChanged();
        _activityDetailsTab?.Refresh();
    });
}
catch (ObjectDisposedException)
{
    await StopRefreshActivityStatePeriodically();
}

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Verification

Steps:

1. Open Workflow Instance Viewer for a running instance so periodic activity refresh is active.
2. Simulate abrupt client disconnect (/_blazor/disconnect) while refresh callbacks are in flight.
3. Observe server behavior during subsequent timer ticks.

Expected outcome:

• No unhandled ObjectDisposedException from disposed IServiceProvider.
• Refresh loop is stopped gracefully for the disconnected circuit.

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Screenshots / Recordings (if applicable)

Not applicable (no UI layout/visual changes).

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Commit Convention

We recommend using conventional commit prefixes:

• fix: – Bug fixes (behavior change)
• feat: – New features
• refactor: – Code changes without behavior change
• docs: – Documentation updates
• chore: – Maintenance, tooling, or dependency updates
• test: – Test additions or modifications

Clear commit messages make reviews easier and history more meaningful.

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Checklist

• The PR is focused on a single concern
• Commit messages follow the recommended convention
• Tests added or updated (if applicable)
• Documentation updated (if applicable)
• No unrelated cleanup included
• All tests pass

Original prompt

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This section details on the original issue you should resolve

<issue_title>Elsa Studio 3.5.2 Occasionally Crashes</issue_title>
<issue_description>Hi,

I am using Elsa Studio version 3.5.2. Occasionally, the related service crashes.
When we review the logs, we see the issue shown below. It is most likely caused by a WebSocket disconnection, after which an object that is still being used by the UI is disposed in an uncontrolled manner, leading to the crash.

info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
Executed endpoint 'Blazor disconnect'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
Request finished HTTP/1.1 POST http://elsastudio-test.xxx.com/_blazor/disconnect - 200 0 - 6.4827ms
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
Request starting HTTP/1.1 POST http://elsastudio-test.xxxx.com/_blazor/disconnect - multipart/form-data;+boundary=----WebKitFormBoundaryvsvstqw9TgzQPSRp 359
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[0]
Executing endpoint 'Blazor disconnect'
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
Executed endpoint 'Blazor disconnect'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
Request finished HTTP/1.1 POST http://elsastudio-test.xxx.com/_blazor/disconnect - 200 0 - 4.2283ms
Unhandled exception. System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'IServiceProvider'.
at Microsoft.Extensions.DependencyInjection.ServiceLookup.ThrowHelper.ThrowObjectDisposedException()
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Elsa.Api.Client.Extensions.DependencyInjectionExtensions.CreateApi[T](IServiceProvider serviceProvider, Uri baseAddress)
at Elsa.Studio.Services.DefaultBackendApiClientProvider.GetApiAsync[T](CancellationToken cancellationToken)
at Elsa.Studio.Workflows.Domain.Services.RemoteActivityExecutionService.ListSummariesAsync(String workflowInstanceId, String activityNodeId, CancellationToken cancellationToken)
at Elsa.Studio.Workflows.Components.WorkflowInstanceViewer.Components.WorkflowInstanceDesigner.GetActivityExecutionRecordsAsync(String activityNodeId)
at Elsa.Studio.Workflows.Components.WorkflowInstanceViewer.Components.WorkflowInstanceDesigner.RefreshSelectedItemAsync(String activityExecutionRecordId)
at Elsa.Studio.Workflows.Components.WorkflowInstanceViewer.Components.WorkflowInstanceDesigner.<>c__DisplayClass124_0.<g__Callback|0>d.MoveNext()
--- End of stack trace from previous location ---
at System.Threading.Tasks.Task.<>c.b__128_1(Object state)
at System.Threading.QueueUserWorkItemCallback.Execute()
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart()</issue_description>

<agent_instructions>Note: 3.5.2 is quite an older version compared to what lives today in main (which is built as 3.7.0 preview packages). Consult online resources to see if this blazor disconnect issue is a known issue and what potential mitigations are, and if this is applicable to what we have in the main branch.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Elsa Studio 3.5.2 Occasionally Crashes #743

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