refactor(config): consolidate commit types into CommitTypeRegistry

Replaces six scattered "chore" literals across TaskEntity, ListEntity,
WorkerHub, ListsIslandViewModel, ListNavItemViewModel and the inline
commit type list in ListSettingsModalViewModel.

src/ClaudeDo.Data/Models/TaskEntity.cs

@@ -32,7 +32,7 @@ public sealed class TaskEntity
     public required DateTime CreatedAt { get; init; }
     public DateTime? StartedAt { get; set; }
     public DateTime? FinishedAt { get; set; }
-    public string CommitType { get; set; } = "chore";
+    public string CommitType { get; set; } = CommitTypeRegistry.DefaultType;
     public string? Model { get; set; }
     public string? SystemPrompt { get; set; }
     public string? AgentPath { get; set; }