feat(tasks): mark tasks and lists as manual

Reminders written down as todos had no home: every task looked like Claude work.
A manual task now shows a MANUAL badge and hides send-to-queue, refine and the
planning session; the queue picker, daily prep and the list handler all skip it,
with a TaskStateService guard so the MCP surface and hub cannot start one either.
Opening a hand-driven ConPTY session stays available on purpose.

A list can be marked manual in its settings, which makes tasks created there
(UI and MCP add_task) start out manual. Toggle per task from its context menu.

src/ClaudeDo.Ui/ViewModels/Islands/ListNavItemViewModel.cs

@@ -12,6 +12,8 @@ public sealed partial class ListNavItemViewModel : ViewModelBase
     [ObservableProperty] private bool _isActive;
     [ObservableProperty] private string? _workingDir;
     [ObservableProperty] private string _defaultCommitType = CommitTypeRegistry.DefaultType;
+    // Reminder list: tasks created here default to manual.
+    [ObservableProperty] private bool _isManual;
     [ObservableProperty] private bool _dropHintAbove;
     [ObservableProperty] private bool _dropHintBelow;
     public string? IconKey { get; init; }