feat(ui): PowerUse-Einstellungen nach Settings -> Ausfuehrung verschieben

Schalter, Zeitfenster und Handoff-Prozent lagen im Usage-Monitor und mussten
in SettingsModalViewModel nur load->save durchgeschleift werden, damit ein
Settings-Speichern sie nicht zurueckwirft. Jetzt gehoeren sie dem General-Tab,
der Monitor ist wieder nur Anzeige + Threshold-Drag, und "Jetzt aktualisieren"
sitzt als Icon in der Titelleiste (neuer ModalShell.HeaderActions-Slot).

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

@@ -30,6 +30,15 @@ public sealed partial class GeneralSettingsTabViewModel : ViewModelBase
     // 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;
+    // PowerUse master switch: a handler run spends the rest of the window unattended. On its own it
+    // changes nothing — the run's LIST must also opt in (list settings → PowerUse).
+    [ObservableProperty] private bool _powerUseEnabled;
+    // Optional local-time window (HH:mm) narrowing when PowerUse applies; both blank = round the
+    // clock. Unparseable input is normalized to null on save, same as the worker does.
+    [ObservableProperty] private string? _powerUseWindowStart;
+    [ObservableProperty] private string? _powerUseWindowEnd;
+    // 5h-usage percentage at which a PowerUse handler session hands off. Clamped 50..99.
+    [ObservableProperty] private int _powerUseHandoffPct = 95;
     // Newline-separated path prefixes excluded from the weekly report.
     [ObservableProperty] private string _reportExcludedPaths = @"C:\Private";
     // 0=Sunday..6=Saturday (System.DayOfWeek); default Wednesday.