fix: resolve critical bugs and improve reliability across worker, data, UI

- Fix worker using wrong DB by defaulting to CurrentUser service account
  and expanding ~ to absolute paths at install time
- Fix DbContext disposed before fire-and-forget by passing taskId instead
  of TaskEntity into RunInSlotAsync, which creates its own context
- Fix ActiveTaskDto property casing mismatch between hub and client
- Move WAL mode PRAGMA before migrations to prevent concurrent lock issues
- Replace FirstAsync with FirstOrDefaultAsync + null guards in tag operations
- Add delete confirmation flow for lists
- Log fire-and-forget exceptions instead of swallowing them
- Broadcast RunCreated event from WorkerHub.RunNow
- Add IDisposable to MainWindowViewModel for event handler cleanup
- Preserve subtask CreatedAt on updates instead of overwriting
- Replace bare catch blocks with Debug.WriteLine logging

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Ui/Services/WorkerClient.cs

@@ -2,6 +2,7 @@ using System.Collections.ObjectModel;
 using Avalonia.Threading;
 using ClaudeDo.Data.Models;
 using CommunityToolkit.Mvvm.ComponentModel;
+using Microsoft.AspNetCore.SignalR;
 using Microsoft.AspNetCore.SignalR.Client;
 
 namespace ClaudeDo.Ui.Services;
@@ -208,9 +209,13 @@ public partial class WorkerClient : ObservableObject, IAsyncDisposable
                     ActiveTasks.Add(new ActiveTask(a.Slot, a.TaskId, a.StartedAt));
             });
         }
-        catch
+        catch (HubException)
         {
-            // Worker might not support GetActive yet
+            // Expected: worker doesn't support GetActive yet
+        }
+        catch (Exception ex)
+        {
+            System.Diagnostics.Debug.WriteLine($"SeedActiveTasksAsync failed: {ex}");
         }
     }