feat(worker): Toggle "Continue on session limit reset" für Usage-Limit-Abbrüche

Klassifiziert einen echten Usage-Limit-Abbruch als eigene FailureReason
"usage_limit" (TaskRunner.ClassifyFailureReason: nur bei terminal_reason
"api_error" plus einem Limit-Muster im gerenderten Fehlertext, nicht an
Status==Failed allein). Neuer Toggle AutoContinueOnUsageLimit (app_settings,
Default aus) unter Settings → General → "Usage limit stop":

- UsageLimitAutoContinueCoordinator feuert pro Task genau einmal ContinueTask
  über OverrideSlotService, sobald das 5h-Fenster (UsageState.Snapshot.FiveHour
  .ResetsAt) tatsächlich zurückgesetzt ist; ein persistenter Marker
  (TaskEntity.UsageLimitAutoContinuedAt) verhindert einen zweiten Anlauf bei
  einem erneuten Limit-Treffer.
- QueueService schedult zusätzlich einen exakten Wake-Timer auf den
  Reset-Zeitpunkt, statt nur auf den 30s-Backstop zu warten.
- Fail-open durchgängig: kein Snapshot/keine Reset-Zeit → kein Timer, kein
  Continue, kein Throw. Toggle aus ändert das heutige Verhalten nicht.

Migration AddUsageLimitAutoContinue fügt beide Spalten hinzu; die von
`dotnet ef migrations add` mitgescaffoldete leere UpdateData auf app_settings
(columns/values: []) erzeugte ungültiges SQL ("near WHERE") und wurde entfernt
— TaskNumberMigrationTests deckte das über den vollen Migrate()-Pfad auf.

src/ClaudeDo.Ui/Services/WorkerClient.cs

@@ -732,7 +732,8 @@ public sealed record AppSettingsDto(
     int UsageThrottleFiveHourSoftPct = 50,
     int UsageThrottleFiveHourHardPct = 65,
     int UsageThrottleSevenDaySoftPct = 50,
-    int UsageThrottleSevenDayHardPct = 65);
+    int UsageThrottleSevenDayHardPct = 65,
+    bool AutoContinueOnUsageLimit = false);
 
 // Per-model run defaults (effort + turn budget) edited in Settings → General.
 public sealed record ModelPresetDto(string Model, string Effort, int MaxTurns);

src/ClaudeDo.Ui/ViewModels/Modals/Settings/GeneralSettingsTabViewModel.cs

@@ -24,6 +24,9 @@ public sealed partial class GeneralSettingsTabViewModel : ViewModelBase
     // Percentage of the 5h/7d Claude usage window at which the autonomous queue pauses. 0 = gate off.
     [ObservableProperty] private int _usageGateFiveHourPct = 80;
     [ObservableProperty] private int _usageGateSevenDayPct = 90;
+    // Off by default: auto-continues a usage-limit-failed task once the 5h window resets, and
+    // wakes a gate-blocked queue exactly at that reset time instead of only the 30s backstop.
+    [ObservableProperty] private bool _autoContinueOnUsageLimit;
     // Newline-separated path prefixes excluded from the weekly report.
     [ObservableProperty] private string _reportExcludedPaths = @"C:\Private";
     // 0=Sunday..6=Saturday (System.DayOfWeek); default Wednesday.

src/ClaudeDo.Ui/ViewModels/Modals/SettingsModalViewModel.cs

@@ -129,6 +129,7 @@ public sealed partial class SettingsModalViewModel : ViewModelBase
                 General.MaxParallelExecutions = dto.MaxParallelExecutions;
                 General.UsageGateFiveHourPct = dto.UsageGateFiveHourPct;
                 General.UsageGateSevenDayPct = dto.UsageGateSevenDayPct;
+                General.AutoContinueOnUsageLimit = dto.AutoContinueOnUsageLimit;
                 _throttleStages = (
                     dto.UsageThrottleFiveHourSoftPct, dto.UsageThrottleFiveHourHardPct,
                     dto.UsageThrottleSevenDaySoftPct, dto.UsageThrottleSevenDayHardPct);
@@ -189,7 +190,8 @@ public sealed partial class SettingsModalViewModel : ViewModelBase
                 _throttleStages.FiveSoft,
                 _throttleStages.FiveHard,
                 _throttleStages.SevenSoft,
-                _throttleStages.SevenHard);
+                _throttleStages.SevenHard,
+                General.AutoContinueOnUsageLimit);
             await _worker.UpdateAppSettingsAsync(dto);
             await Prime.SaveAsync();
             await OnlineInbox.SaveAsync();

src/ClaudeDo.Ui/Views/Modals/SettingsModalView.axaml

@@ -237,6 +237,10 @@
                                    HorizontalAlignment="Left" Width="140"/>
                   </StackPanel>
                 </StackPanel>
+                <CheckBox IsChecked="{Binding General.AutoContinueOnUsageLimit, Mode=TwoWay}"
+                          Content="{loc:Tr settings.general.autoContinueOnUsageLimit}"/>
+                <TextBlock Text="{loc:Tr settings.general.autoContinueOnUsageLimitHint}"
+                           Opacity="0.6" FontSize="12" TextWrapping="Wrap"/>
               </StackPanel>
             </StackPanel>
           </ScrollViewer>