feat(ui): PowerUse-Toggle im Usage-Monitor, Opt-in pro Liste

Der Toggle sitzt unter den Gauges im Usage-Monitor, weil "das restliche Fenster
ausnutzen" eine Entscheidung ist, die man beim Blick auf das restliche Fenster
trifft. Er speichert sofort per Read-modify-write, gleiche Disziplin wie
SaveStagesAsync, damit er keine Felder ueberschreibt, die er nicht besitzt.

Zwei Stellen, die das Opt-in still ausgeschaltet haetten:
- WorkerHub.UpdateListConfig loescht die Config-Zeile, wenn alle Felder leer
  sind. PowerUseAllowed muss in diese Leer-Pruefung, sonst verschwindet das
  Opt-in sofort wieder, wenn es das einzige gesetzte Feld ist.
- SettingsModalViewModel baut das AppSettingsDto positional neu auf. Ohne
  Round-trip haette jedes Speichern der Settings PowerUseEnabled auf den
  Record-Default false zurueckgesetzt. Gleiches Muster wie _throttleStages.

Das Handoff-Budget ist als Spinner in Settings -> General editierbar, weil es
auch fuer normale (interaktive) Handler-Runs gilt und nicht an PowerUse haengt.
Das Addendum selbst ist ueber Settings -> Files anpassbar.

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

@@ -45,6 +45,10 @@ public sealed partial class ListSettingsModalViewModel : ViewModelBase
     // Optional post-merge verification command (build/test), run in WorkingDir after a merge
     // lands; a non-zero exit keeps the task out of Done instead of silently reporting merged.
     [ObservableProperty] private string _verifyCommand = "";
+    // Per-list opt-in for PowerUse. A handler run on this list only goes unattended (no questions,
+    // harvests new work, longer handoff chain) when this AND the global switch in the usage monitor
+    // are both on. Off by default — the global switch alone must never change a list's behaviour.
+    [ObservableProperty] private bool _powerUseAllowed;
     // Dropdown hidden entirely when no ticket-system base URL is configured (Settings → Files tab).
     // Icon key into the UI icon library (IconKeyConverter -> "Icon.<key>" StreamGeometry).
     [ObservableProperty] private string _icon = DefaultIcon;
@@ -110,6 +114,7 @@ public sealed partial class ListSettingsModalViewModel : ViewModelBase
         await Agent.LoadForListAsync(listId, ct);
         var cfg = await _worker.GetListConfigAsync(listId);
         VerifyCommand = cfg?.VerifyCommand ?? "";
+        PowerUseAllowed = cfg?.PowerUseAllowed ?? false;
 
         var ticketSettings = TicketSettingsTabViewModel.FeatureEnabled
             ? await _worker.GetTicketSettingsAsync()
@@ -149,9 +154,12 @@ public sealed partial class ListSettingsModalViewModel : ViewModelBase
         // Never null here, or an explicit unlink would silently fail to reach the worker.
         var ticketProjectId = TicketsAvailable ? (SelectedTicketProject?.Id ?? 0) : (int?)null;
 
+        // Always explicit (never null) — this modal owns the checkbox, so unchecking it has to reach
+        // the worker as a real false rather than a "leave it alone".
         await Agent.SaveAsync(
             string.IsNullOrWhiteSpace(VerifyCommand) ? null : VerifyCommand,
-            ticketProjectId);
+            ticketProjectId,
+            PowerUseAllowed);
 
         Saved = true;
         CloseAction?.Invoke();

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

@@ -30,6 +30,7 @@ public sealed partial class FilesSettingsTabViewModel : ViewModelBase
     public string RetryPromptPath { get; } = PromptFiles.PathFor(PromptKind.Retry);
     public string DailyPrepPromptPath { get; } = PromptFiles.PathFor(PromptKind.DailyPrep);
     public string WeeklyReportPromptPath { get; } = PromptFiles.PathFor(PromptKind.WeeklyReport);
+    public string PowerUsePromptPath { get; } = PromptFiles.PathFor(PromptKind.PowerUseAddendum);
 
     public ObservableCollection<CustomizedPromptRowViewModel> CustomizedPrompts { get; } = new();
 

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

@@ -27,6 +27,9 @@ public sealed partial class GeneralSettingsTabViewModel : ViewModelBase
     // 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;
+    // Cap on a list-handler run's wait<->merge handoff chain. 4 = two merge rounds (the long-standing
+    // default); raise it for runs meant to keep going for hours. Bounds a runaway chain, so never 0.
+    [ObservableProperty] private int _listHandlerMaxHandoffs = 4;
     // 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

@@ -130,6 +130,10 @@ public sealed partial class SettingsModalViewModel : ViewModelBase
     // carried through load→save verbatim so saving Settings can never reset a dragged value.
     private (int FiveSoft, int FiveHard, int SevenSoft, int SevenHard) _throttleStages = (50, 65, 50, 65);
 
+    // Same deal: the PowerUse master switch is toggled on the usage monitor. Carried load→save so
+    // opening and saving Settings can't switch it off behind the user's back.
+    private bool _powerUseEnabled;
+
     public async Task LoadAsync()
     {
         IsBusy = true;
@@ -147,6 +151,11 @@ public sealed partial class SettingsModalViewModel : ViewModelBase
                 General.UsageGateFiveHourPct = dto.UsageGateFiveHourPct;
                 General.UsageGateSevenDayPct = dto.UsageGateSevenDayPct;
                 General.AutoContinueOnUsageLimit = dto.AutoContinueOnUsageLimit;
+                General.ListHandlerMaxHandoffs = dto.ListHandlerMaxHandoffs;
+                // Owned by the usage monitor, not editable here — but it MUST be round-tripped,
+                // because SaveAsync rebuilds the whole DTO positionally and would otherwise write
+                // the record default (false) back and silently switch PowerUse off.
+                _powerUseEnabled = dto.PowerUseEnabled;
                 _throttleStages = (
                     dto.UsageThrottleFiveHourSoftPct, dto.UsageThrottleFiveHourHardPct,
                     dto.UsageThrottleSevenDaySoftPct, dto.UsageThrottleSevenDayHardPct);
@@ -213,7 +222,9 @@ public sealed partial class SettingsModalViewModel : ViewModelBase
                 _throttleStages.FiveHard,
                 _throttleStages.SevenSoft,
                 _throttleStages.SevenHard,
-                General.AutoContinueOnUsageLimit);
+                General.AutoContinueOnUsageLimit,
+                _powerUseEnabled,
+                General.ListHandlerMaxHandoffs);
             await _worker.UpdateAppSettingsAsync(dto);
             await Prime.SaveAsync();
             await OnlineInbox.SaveAsync();

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

@@ -100,6 +100,45 @@ public sealed partial class UsageMonitorModalViewModel : ViewModelBase
     [ObservableProperty]
     private IReadOnlyList<UsageGaugeRowViewModel> _gaugeRows = Array.Empty<UsageGaugeRowViewModel>();
 
+    /// <summary>
+    /// PowerUse master switch. It lives here rather than in Settings because turning it on is a
+    /// "spend the rest of the window" decision, made while looking at how much window is left.
+    /// On its own it changes nothing — a list-handler run only goes unattended when its LIST also
+    /// opted in (list settings → PowerUse), so this can stay on without affecting other lists.
+    /// </summary>
+    [ObservableProperty] private bool _powerUseEnabled;
+
+    // Set while LoadAsync writes the stored value in, so seeding the property doesn't immediately
+    // write it straight back to the worker.
+    private bool _loadingPowerUse;
+
+    partial void OnPowerUseEnabledChanged(bool value)
+    {
+        if (_loadingPowerUse) return;
+        _ = SavePowerUseAsync(value);
+    }
+
+    /// Read-modify-write, same discipline as SaveStagesAsync: never clobber a field this modal
+    /// doesn't own.
+    private async Task SavePowerUseAsync(bool value)
+    {
+        try
+        {
+            var settings = await _worker.GetAppSettingsAsync();
+            if (settings is null)
+            {
+                ErrorReported?.Invoke(Loc.T("vm.usageMonitor.powerUseSaveFailed", Loc.T("vm.settingsModal.workerOffline")));
+                return;
+            }
+
+            await _worker.UpdateAppSettingsAsync(settings with { PowerUseEnabled = value });
+        }
+        catch (Exception ex)
+        {
+            ErrorReported?.Invoke(Loc.T("vm.usageMonitor.powerUseSaveFailed", ex.Message));
+        }
+    }
+
     public bool IsStale => Snapshot?.IsStale == true;
     public string? LastError => Snapshot?.LastError;
     public bool IsGateBlocked => Snapshot?.IsGateBlocked == true;
@@ -148,6 +187,15 @@ public sealed partial class UsageMonitorModalViewModel : ViewModelBase
             Snapshot = snapshot;
             _worker.UsageUpdatedEvent -= OnUsageUpdated;
             _worker.UsageUpdatedEvent += OnUsageUpdated;
+
+            var settings = await _worker.GetAppSettingsAsync();
+            if (settings is not null)
+            {
+                _loadingPowerUse = true;
+                try { PowerUseEnabled = settings.PowerUseEnabled; }
+                finally { _loadingPowerUse = false; }
+            }
+
             ApplyPresetRange(SelectedPresetDays);
             await LoadUsageDataAsync();
         }