Hardened background work against disconnected circuits (#937)

app/MindWork AI Studio/Assistants/AssistantBase.razor.cs

@@ -170,10 +170,15 @@ public abstract partial class AssistantBase<TSettings> : AssistantLowerBase wher
         }
         
         this.formChangeTimer.AutoReset = false;
-        this.formChangeTimer.Elapsed += async (_, _) =>
+        //
+        // Mind the missing async here: a timer hands its elapsed event to a thread pool thread, where an
+        // async handler has nobody to hand its exception to. Such an exception is not merely unobserved,
+        // it is unhandled, and it takes the app down with it. Observing the task keeps it contained.
+        //
+        this.formChangeTimer.Elapsed += (_, _) =>
         {
             this.formChangeTimer.Stop();
-            await this.OnFormChange();
+            this.OnFormChange().Observe($"{nameof(AssistantBase<TSettings>)}: handling a form change");
         };
         
         this.MightPreselectValues();
@@ -327,7 +332,7 @@ public abstract partial class AssistantBase<TSettings> : AssistantLowerBase wher
         Array.Resize(ref this.InputIssues, this.InputIssues.Length + 1);
         this.InputIssues[^1] = issue;
         this.InputIsValid = false;
-        _ = this.RefreshAssistantUIAsync();
+        this.RefreshAssistantUIAsync().Observe($"{nameof(AssistantBase<TSettings>)}: rendering an added input issue");
     }
     
     /// <summary>
@@ -337,7 +342,7 @@ public abstract partial class AssistantBase<TSettings> : AssistantLowerBase wher
     {
         this.InputIssues = [];
         this.InputIsValid = true;
-        _ = this.RefreshAssistantUIAsync();
+        this.RefreshAssistantUIAsync().Observe($"{nameof(AssistantBase<TSettings>)}: rendering cleared input issues");
     }
 
     protected void CreateChatThread()
@@ -733,11 +738,11 @@ public abstract partial class AssistantBase<TSettings> : AssistantLowerBase wher
     private void OnMediaImportStateChanged(MediaImportOwner owner)
     {
         if (owner == this.CurrentMediaImportOwner)
-            _ = this.InvokeAsync(async () =>
+            this.InvokeAsync(async () =>
             {
                 await this.ConsumeMediaOutcomeAsync();
                 this.StateHasChanged();
-            });
+            }).Observe($"{nameof(AssistantBase<TSettings>)}: consuming a media import outcome");
     }
 
     /// <summary>Consumes a terminal media notification when this assistant is visible.</summary>

app/MindWork AI Studio/Assistants/I18N/AssistantI18N.razor.cs

@@ -90,7 +90,7 @@ public partial class AssistantI18N : AssistantBaseCore<SettingsDialogI18N>
             this.customTargetLanguage = string.Empty;
         }
 
-        _ = this.OnChangedLanguage();
+        this.OnChangedLanguage().Observe($"{nameof(AssistantI18N)}: applying a language change");
     }
     
     protected override bool MightPreselectValues()

app/MindWork AI Studio/Assistants/LogViewer/AssistantLogViewer.razor.cs

@@ -460,7 +460,7 @@ public partial class AssistantLogViewer : MSGComponentBase
     {
         this.StopAutoRefresh();
         this.autoRefreshCancellationTokenSource = new CancellationTokenSource();
-        _ = this.AutoRefreshLoopAsync(this.autoRefreshCancellationTokenSource.Token);
+        this.AutoRefreshLoopAsync(this.autoRefreshCancellationTokenSource.Token).Observe($"{nameof(AssistantLogViewer)}: refreshing the log automatically");
     }
 
     private void StopAutoRefresh()

app/MindWork AI Studio/Assistants/VisualBriefing/VisualBriefingAssistant.razor.Build.cs

@@ -246,14 +246,14 @@ public partial class VisualBriefingAssistant
         if (this.selectedBriefing?.BriefingId != briefingId)
             return;
 
-        _ = this.InvokeAsync(() =>
+        this.InvokeAsync(() =>
         {
             if (this.selectedBriefing?.BriefingId != briefingId)
                 return;
 
             this.latestBuild = this.BuildProgressService.GetLatest(briefingId);
             this.StateHasChanged();
-        });
+        }).Observe($"{nameof(VisualBriefingAssistant)}: rendering the build progress");
     }
 
     /// <summary>

app/MindWork AI Studio/Assistants/VisualBriefing/VisualBriefingAssistant.razor.Projects.cs

@@ -265,7 +265,7 @@ public partial class VisualBriefingAssistant
             : briefing.Versions.OrderByDescending(version => version.VersionNumber).FirstOrDefault()?.RevisionId ?? Guid.Empty;
 
         if (revisionId != Guid.Empty)
-            _ = this.SelectRevisionAsync(revisionId);
+            this.SelectRevisionAsync(revisionId).Observe($"{nameof(VisualBriefingAssistant)}: selecting a revision");
         else
         {
             this.selectedRevisionId = Guid.Empty;

app/MindWork AI Studio/Assistants/VisualBriefing/VisualBriefingAssistant.razor.Sources.cs

@@ -136,7 +136,7 @@ public partial class VisualBriefingAssistant
             !Guid.TryParse(owner.Id, out var briefingId))
             return;
 
-        _ = this.InvokeAsync(async () =>
+        this.InvokeAsync(async () =>
         {
             await this.ConsumeMediaOutcomeAsync(owner);
             if (!this.MediaTranscriptionService.IsBusy(owner))
@@ -152,7 +152,7 @@ public partial class VisualBriefingAssistant
             }
 
             this.StateHasChanged();
-        });
+        }).Observe($"{nameof(VisualBriefingAssistant)}: consuming a media import outcome");
     }
 
     /// <summary>

app/MindWork AI Studio/Assistants/VisualBriefing/VisualBriefingAssistant.razor.cs

@@ -157,7 +157,7 @@ public partial class VisualBriefingAssistant : MSGComponentBase
         this.BuildProgressService.Changed += this.BuildProgressChanged;
         await this.ReloadListAsync();
         await this.ConsumePendingMediaOutcomesAsync();
-        _ = this.MonitorSourceStatusAsync(this.sourceMonitorCancellation.Token);
+        this.MonitorSourceStatusAsync(this.sourceMonitorCancellation.Token).Observe($"{nameof(VisualBriefingAssistant)}: monitoring the source status");
         var deferredInstruction = this.MessageBus.TakeDeferredMessages<string>(Event.SEND_TO_VISUAL_BRIEFING_ASSISTANT).LastOrDefault();
 
         if (!string.IsNullOrWhiteSpace(deferredInstruction))

app/MindWork AI Studio/Assistants/VisualBriefing/VisualBriefingBuildProgress.razor.cs

@@ -56,7 +56,7 @@ public partial class VisualBriefingBuildProgress : MSGComponentBase
     protected override async Task OnInitializedAsync()
     {
         await base.OnInitializedAsync();
-        _ = this.MonitorBuildDurationAsync(this.durationMonitorCancellation.Token);
+        this.MonitorBuildDurationAsync(this.durationMonitorCancellation.Token).Observe($"{nameof(VisualBriefingBuildProgress)}: monitoring the build duration");
     }
 
     protected override void OnParametersSet()