feat(claude-do): UI: Gate-Schwellen im Settings-Modal (General)

Macht die zwei Schwellen einstellbar. Setzt den Data-Subtask (Felder in `app_settings`) und den Hub-Subtask voraus.

**Zu bauen**
1. `AppSettingsDto` durchziehen: `WorkerHub` (`GetAppSettings` / `UpdateAppSettings`) und der UI-seitige Record in `WorkerClient.cs` bekommen `UsageGateFiveHourPct` und `UsageGateSevenDayPct`.
2. `GeneralSettingsTabViewModel`: zwei `[ObservableProperty]`-Felder, Validie

ClaudeDo-Task: 06068810-5b5c-4635-80dd-62eeba89fb8c

src/ClaudeDo.Worker/Hub/WorkerHub.cs

@@ -43,7 +43,9 @@ public record AppSettingsDto(
     int StandupWeekday,
     int DailyPrepMaxTasks,
     List<string>? SessionSkills = null,
-    List<ModelPresetDto>? ModelPresets = null);
+    List<ModelPresetDto>? ModelPresets = null,
+    int UsageGateFiveHourPct = 80,
+    int UsageGateSevenDayPct = 90);
 
 // Per-model run defaults (effort + turn budget) edited in Settings -> General.
 public record ModelPresetDto(string Model, string Effort, int MaxTurns);
@@ -378,7 +380,9 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
             row.DailyPrepMaxTasks,
             SkillsFromJson(row.SessionSkills),
             Data.Models.ModelPresets.Parse(row.ModelPresets)
-                .Select(p => new ModelPresetDto(p.Model, p.Effort, p.MaxTurns)).ToList());
+                .Select(p => new ModelPresetDto(p.Model, p.Effort, p.MaxTurns)).ToList(),
+            row.UsageGateFiveHourPct,
+            row.UsageGateSevenDayPct);
     }
 
     public async Task UpdateAppSettings(AppSettingsDto dto)
@@ -406,6 +410,8 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
                 ? Data.Models.ModelPresets.Serialize(
                     dto.ModelPresets.Select(p => new ModelPreset(p.Model, p.Effort, p.MaxTurns)))
                 : Data.Models.ModelPresets.SerializeDefaults(),
+            UsageGateFiveHourPct = dto.UsageGateFiveHourPct,
+            UsageGateSevenDayPct = dto.UsageGateSevenDayPct,
         });
     }